# Casting Rumford Throat



## bytor

Hello All,
We have a few Rumford fireplaces on the horizon. In the past we've used pre-cast components supplied by Superior Clay, Buckley Rumford, Rumford.com et al.... This time around, I'd like to cast our own throat systems with refractory cement/concrete. I know there is probably a learning curve to this, but I've got time to practice, so to speak. 
I'm wondering if anyone can offer any advice or tips on how you would go about this.
What refractory materials would you recommend? Do you cast in place or prefab the throat/lintel elsewhere and then install? Do you use re-bar in refractory castings? etc. etc.
Thanks for any help you can offer.


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## artisanstone

I'm interested in this as well. I know that Superior Clay sells a castable refractory material... Let us know what you find out.


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## Tscarborough

I just went outside and looked at one to see how they molded it. It appears that the outside is formed and the inside is not. That means they use an exterior form and hand apply the material to it. Doable, but that is a complex shape. What would you use for a mold?

If I were going to do it, I would cast the quarter round throat pieces and the coving. Much easier to do.


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## CanCritter

pics plz when ya do


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## jvcstone

why not build the throat and smoke chamber yourself from brick.

Never used a kit of any sort.

JVC


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## jomama

This may be a dumb (or ignorant even) question, but have you used the 12" throat sections they offer before? They're a ton cheaper than the one piece. I've never actually cast them before, but always was under the impression that they were cast in place. I'm sure Buckley has some pics somewhere on his sight.

As for another alternative, when I built the one on my patio last year, I used a section of concrete culvert pipe (removed from my own ditch a year earlier, I considered it my contribution to the "green" moovement :laughing & plastered to layers of Heatstop II onto it. I found the curve of the 15" I.D. pipe matched almost perfectly to the Buckley throat. I don't burn this FP that often or very hot, but the throat has held up fine so far. As a matter of fact, when checking temps with the infared gun, I don't think it ever really even gets that hot when compared to the backwall.


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## jomama

Oops, forgot, a pic tells a thousand words.........


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## bytor

Thanks everyone... I was thinking along the lines of tsscarborough... forming and casting a 1/4 round, a more 'solid' version of jomama's picture. I would obviously build up the side and back walls higher with the firebrick and fill in the voids between the firebrick and the 1/4 round cast piece with cut firebrick/refractory cement. As jomama says, similar to the 1/4 round segments that Buckley Rumford sells. What I was hoping though, is to make it a one piece structural lintel. ie. for a 3' firebox opening, I would cast something say around 52" long, by roughly 12" high by 12" wide with the radius on one side... This raises a question about the introduction of re-enforcing steel into the mix... would the buildup of heat eventually cause metal and refractory to expand at different rates? I'm encouraged by the fact that jomama's infrared gun didn't register too much heat buildup. I'll certainly keep you all up to date on anything i find out...


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## Tscarborough

He just showed us how; cast the proper diameter tube and cut it into 1/4s. Genius!


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## lukachuki

jvcstone said:


> why not build the throat and smoke chamber yourself from brick.
> 
> Never used a kit of any sort.
> 
> JVC


John this is 2010...you keep forgetting!


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## lukachuki

jomama said:


> Oops, forgot, a pic tells a thousand words.........
> 
> View attachment 30265


who said forums weren't helpful....very nice solution.


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## dbrons

yeah very nice. I have a different way when I want to build what I call a "modified rumford".

I set a plywood form and then lay in split firebricks dry. I then place a grid of #3 rebar and a couple buckets of concrete mix. This doesn't give you that curve, rather an incline, but it works fine, looks good, and is not that difficult.

Dave


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## artisanstone

Now that is exceptional brickwork!:thumbsup:


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## Stephen M

do you have any more pictures of the process for building the throat? thanks


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## CJKarl

jvcstone said:


> why not build the throat and smoke chamber yourself from brick.
> 
> Never used a kit of any sort.
> 
> JVC


Have always used brick and parge it.


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## dbrons

If your asking me, I do have this that shows the firebricks which were laid on the plywood form. Opening was crossed over with a 4"block, then a 6" bondbeam. I coated the firebricks with fireclay then filled in behind with cement and rebar.

Now keep in mind this is not something I claim will work in any other situation. I just had a woman who wanted a 50"X50" opening and the traditionally shaped rumford wouldn't work because of some built-in bookshelves and other considerations in the room.


Dave


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## JBM

Its been a while since I have used an exact level, I miss the days of looking sideways into the bubble on my 2 footer :no:


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## JBM

To chirp in on this old thread, anyone looking to build a Rumford without the kit should look at how Bytor finished off the top of his firebox in the last picture post he made. Stepping the brick and continuing the firebox is exactly how it should be done. Then all is needed is simply building the front of the throat, hammer cut an angle brick and parge it off nice and smooth.

The only thing is an angle iron is needed to span the opening, and the standard dampers wont fit on the top.

Solution would be to order the Rumford dampers, have them specialty made like Bytor, or use a lemance damper.

It is worth noting that if the measurements of the firebox is altered radiant heat loss will result. Once the side walls begin to get straightened out, the amount of radiant heat that reflects into the room goes down drastically.

It is tough to say that home made versions of a Rumford work just fine without having first hand experience with a Rumford on a daily basis. 

In my previous house I had a 36" Rumford and I was VERY concerned that our couch would catch fire from spontaneous combustion, or at the very least melt the fabric. The couch was positioned 5' away from the opening as well. 

If any more then 1 log and some hot embers were burning the room would get too hot to even sit in.

Dozens of my friends have had me build various fireplaces with the standard 20" box 10 courses tall, and none of them have ever come close to producing this kind of heat. Some would feel warm, but thats about it.

So, no disrespect, but when people say that build a Rumford without using any of the firebox dimensions or the throat system, I am weary of putting it in the same BTU category of a true Rumford without first hand experience from both a true Rumford as well as the modified version.


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## dbrons

They used to make those Exact levels near where I went to school in New Jersey. I don't use them myself anymore either, they don't make them like they used to.

I looked and the picture you mention of Bytor's is no longer there for some reason. I too liked the construction and especially the flat damper.

I will say though that I had to copy a fireplace in a Frank LLoyd Wright designed home in Escondido CA and the throat was parged and it had crumbled away a lot. The guy would burn really big logs in what is kind of a 3 sided fireplace.

Anyway, copying that 3 faceted throat I used a form and firebricks rather than plaster hoping it would hold up better. 

Though I understand what you're saying about the dimensions of a classic Rumford I would just point out that the fireplaces I build here in California aren't about being in the same BTU league as a Rumford. Most are outdoors and lots of my fireplaces never even see a real log. 

Dave


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## dom-mas

When i was in school and we were doing "fireplace week" or whatever, we had a very reputable guy come in and give us some very good info. One of the lessons was on casting rumford throats. Unfortunately I wasn't on the team that was doing that I was on the team building one using brick and parging however we did get a demonstration and did a lot of on looking.

The technique was to use very wet sand in a box and make a reverse of the throat. Pour in the castable refractory, no steel that i can remember but it was mixed with sand. Let harden, then sand the bejezzus out of it to make it roll as best you could. For large throats it was done in 2 pieces so they were manageable.

Not a real precise answer but as I say i didn't have first hand knowledge.

JBM, I've done "modified" rumfords, basically because they were small and if they had the proper ratios there would have been no room for wood (only about 8" deep if I remember). With a real Rumford throat and still relatively shallow firebox, (I think i increased to 12" deep) the homeowners later told me they had to open windows in the middle of winter cause it got so warm in the room. The chimney was located inside the house however.


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## JBM

I found it!

I spent 2 hours on Google looking for this, anyways, this summer I am going to be ordering this for future Rumfords, as thats the direction I am taking my new construction chimneys.

http://www.hart-pagosa.com/Hart-Rumford/index.html

Just need to come up with a refractory concrete mix to use in them.


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## 2low4nh

wow those are pricey


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## dom-mas

JBM said:


> I found it!
> 
> I spent 2 hours on Google looking for this, anyways, this summer I am going to be ordering this for future Rumfords, as thats the direction I am taking my new construction chimneys.
> 
> http://www.hart-pagosa.com/Hart-Rumford/index.html
> 
> Just need to come up with a refractory concrete mix to use in them.


I would google "castable refractory" I'm sure something good will come up. No large aggregate used from what I recall, just castable, sand and water, unless the castable is already wet but that would be expensive


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## Fancis Casini

*slant rumfords*

Hey guys, I came across this thread just today and it seems like a good place for discussion. 

We are 4th gen masons from CT. and longtime Orton Style Rumford Builders. I've been doing them since 70 when I first read his book. 

It's ashamed what's being said about Vrest and the slanted version of the Rumford and when one notes who these people are and their agenda to sell prefab throats etc for the so called "True Rumford", eyebrows should raise.
They privilege themselves to finish writing history by stating, Count Rumford failed in attempt to get his experimental slanted fireplaces to work, therefore he was silent when he promised to elaborate on his findings. 
Ben Franklin had long invented the stove that was quickly catching on, while the Count was no doubt encountering many problems trying to adopt this new style into pre-existing,thick front walled fireplaces.
He made mention in his footnote about the only slant he adopted into a bedroom chimney with just a 4'' front wall. 
He was used to keeping the back vertically plumb just 4'' behind the face wall which would only be a depth of 8''. He wanted to deepen it to 12 or 14'' for a coal basket or wood logs, so he did so, but only up to 10'' above the fire then straight up again. 
This was more like a cove at the lower back that undoubtedly caused mass turbulence the longer it burned, especially a wood fire.
The rhetoric circulating today, suggesting that the Count's potter failed in fabricating a clay throat to suffice his experimental slant firebox, and finally, some 200 years later it's been achieved [for a straight back?] 
IF this smoke blowing is fooling anyone it's these young masons, whom only know what they're being told.
Let's remember that Rumford had only partially leaned his wall up to 10'' above the fire in the bedroom f.p. and now was trying to adopt a slant for larger deeper fireplaces on the lower floors because he was amazed with the increased radiant heat. 
For him to slant an already deep enough box he'd end up with a deeper box than needed, unless he completely removed the front wall up to about 7 feet or so and perhaps higher on larger f.places, in order to bring the throat forward enough to provide a slanted back wall. 
If he ever continued in his experimentation, even after realizing the extra work and cost, he perhaps would've needed Harry Potter to change direction from a forward lean into a backward lean, once he past the throat. I.E.he now has a longer throat that is under the front wall and needs immediate reversal of the chamber in order to clear above fireplaces, and perhaps even side angling as those multi fireplace chimneys were very busy inside with thick stone flues, I know I climbed in them and rebuilt them,.. full of mice droppings and other. 
One wouldn't have to stretch his imagination to agree that Count Rumford opted to move on, to compete with Ben in developing his own stove [which he did], after realizing that straight backs were best suited for rebuilding those monstrosities, just as they are better suited for exterior chimneys today, having the throat and chamber at the rear which makes for easy clearance of headers and air spaces.

But there can be no better choice of a firebox than the slant, when the chimney is interior. 
This is a point when one must decide on which firebox style works better and where. 
This question is often met with rhetorical wizardry on behalf of the marketers, whom make statements like, Slanted Ortons are smoke prone due to turbulence coming from the slanted wall which casts smoke into the room; They can't accommodate a Ti Pi fire therefore smoke that gets emitted from the ends of logs, and is cast forward instead of being high and near the throat, like the "true rumfords"; They don't have rounded breast ;their throats are longer and as much as 1/3 larger in area, resulting in a bigger heat loss up the chimney!; And the straight back has passed epa tests for combustion, suggesting doubt a slant with out the 
ti pi fire and it's longer throat will pass.
I will address the epa part first by saying that if the same dry wood is used in a slant or in most any good drawing fireplace, and a large flamed fire is supplied as was in their test, results will be close. 
Secondly; To end the rest of the claims I've sent videos to certain people whom were a bit taken aback when they witnessed my 18 year old 50'' slant burning smokeless with the damper at 2-3/4'' the face virtually unstained by eddys.
This killed all the birds with one stone, so to speak, because it shows that no matter what shape the back wall takes, the same throat area for both can suffice a clean draw. 
With this being proved, and the slant being the better radiator as even the Count acknowledged, is attest to why for the past 150 years, the slant has been the choice over the straight. 
I've only done video visuals of my damper but the next one will show a measured 2''x2-3/4'' inserted into the blade which is fabricated by me. 
I like to use my fabricated dampers which I believe enable a thinner throat, although I have adopted cast irons to suffice but not nearly cabable of choking to the same depth. 
These fabricated dampers are actually lintel dampers and very handy.Key is proper configuration so when the blade is choked it doesn't cause turbulence. 
Lastly to elucidate on Orton's discussing how the slant was time morphed into the smoke prone mess [that these nay-sayers refer to in general and braket together] during the late 50s and 60s. 
Raised hearths became popular, and shortened the height of the openings on slants. 
This along with starting the slant too high, made the slant's angle too great. 
Then came the cast-iron dampers with the big front flanges, with instructions to place them 3 to 6'' above the lintel, and worse many masons put them at the same height thinking the inclined blade would suffice for a smoke collector before the throat. Or an arched opening would flush out with the flange at mid point [the center of the arch]
I can recall giving Orton's book to building inspectors back then so they could enforce proper practice.
This took many years and in fact many architects and inspectors are just now coming around to Orton's descriptions just as the hecklers are too, as they point out some of his add libbed statements such as, "Rumford slanted his fire-backs" and "cold air descends down the back of the chimney as heat rises on the inside then rolls and mixes". 
Perhaps they are right in saying air cannot flow bi directional simultaneously within a pipe! 
But I say WITHIN A FIREPLACE's chimney, multiple pressure differences constantly occur, resulting in either a full upward flow of heated air coming from inside, this can be from a force full large fire [injection style];or a suction style via good cold outside air movement and ample make up air; A vacuum like scenario, where outside movement is sucking but inside air is not ample to replace [negative].
The latter will cause hot cold turbulence in segments of the chimney all the way up, simulating simultaneous bidirectional currents, and this is what gives impression of constant up down air in a chimney. No matter though, because on sluggish days especially when a low fire is present, a pulsating type draw and eddys will occur if the throat isn't at the front of a shelf and chamber.
I've had this discussion and they claim it makes no difference where the throat is positioned, nor the chamber, BUT THEY ENCOURAGE LARGE TI PI FIRES, bearing out their injection via rounded breast theory and necessity of a ti pi.
It is a longtime observation of mine that slants actually are better suction devices with their longer throats up close behind the face, in contrast to straights being straight up and out the back.
They both draft [suck] on good drafting days but the slant is the better with it's long [true full length] throat and when choked thin it actually increases in strength tremendously actually enebling further choking. This is not as fool proof with slants and unlike the straights, when draft is not so good, a force fire cannot push through as easy, therefore the back wall slope;upper throat / "damper" and chamber need to be right or turbulence will occur. 
One very nice equalizer is that when the longer upper body of the slant [including the shelf and chamber] get hot, it's like someone can put a plywood over the chimney and it'll push it off.
I have videos and pics if anyone would like to view them, nothing is for sale it's just for knowledge. In fact the last video was done with a 12'' elm log on a pea soup night which absolutely would devastate most straights with a standard fire......heck who wants to bother stoking and poking a ti pi all night...lol! 

Fank Casini Oxford Ct. http://www.facebook.com/pages/Casini-Masonry/159609824086030


http://www.youtube.com/results?sear....0.0.0.95.599.9.9.0...0.0...1ac.1.-ocvCdwX5Uc


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## Rockmonster

Wow.


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## Tscarborough

Nothing like having an argument with yourself.


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## Mud Master

What? 

Could you repeat that?


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## dom-mas

heck of a first post.


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## JBM

I feel like you have a lot to share, but it is tough to make out a specific point you are making.


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## superseal

Do you use firebrick in your boxes? - video looks like regular clay.

that 12" elm is quite the site :laughing:


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## dom-mas

JBM said:


> I feel like you have a lot to share, but it is tough to make out a specific point you are making.


I would say that his point is that "true" rumfords don't draw as well as Orton? rumfords do when you have a lazy smoky fire, particularly on high pressure evenings


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## Fancis Casini

Yesterday's post in a nutshell 

There is no better chioce for a interior chimney-ed fireplace than the Orton They work great.

The straights are better suited on exteriors where the flue has to clear framing or in basements when placed against the foundation.

All young masons should learn Ortons they are very rewarding, and if anyone designs their own home put the fireplace inside and close to the middle of the house, like the old timers did.They work great warm and tall......lol

By the way Jim Buckley has seen my video and was amazed with the throat being a bit smaller than the [straight] true rumford's throat.

He suggested I paint a plywood black and place thermo couplers on it, 5 feet in front of the fire, to compare with his. 

I never did due to the fact we had equal throats but I had the 8'' forward slanting back wall. Common sense! Yet he / they still claim mechanical and thermal superiority?

It's too bad they don't get smart and change [or customize] those pre fab breast / throats [esp.on the bigger boxes]to have the throat more forward, thereby enabling a longer damper and a thinner than thick breast. 
This would more than likely enable them to bring the fire more forward instead of the usual [sure draw] ti pi fire.

Where's Harry D. Potter when u need him.

As to why no firebrick they don't look as good for colonial stlye.

The firebox brick are good common brick.They last long ,mine are about 18 years used and are somwhat spalled at the baotton but it looks better that way esp on colonials or salt boxes like mine.
I use to use harvard gonics which were like iron but thy spall sooner. I have 14'' of masonry at the base including the fire brick; 2'' of clippings for expansion an 8'' more of brick. I try and not use light weight block there because they expand so damed much.


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## JBM

I appreciate your passion I really do, but I personally built a straight back in one of my previous houses and it was obnoxiously hot. 

Unless in a wide open room it is not practical to keep and maintain a large tee pee sized fire as it simply will to hot.

An occasional log on top of the hot coals is all I could put in my fireplace unless I was in the other room. This was only a 36" opening as well.

At the end of the day I choose Jim's throat and design as my specialty fireplace. If everything is equal, I think it simply looks better.


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## CJKarl

Kind of my thought. How hot is hot? You can debate the thermal properties of each all day long. If it burns and doesn't smoke it's a good design in my book. The rest is aesthetics.


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## Fancis Casini

*If it burns and doesn't smoke it's a good design in my book.*

I like that....u sleep at night! Tell me does that logic go for cigars? lol: laughing: 

Well now maybe u see what is important to one is moot to another.

The only reason I post this stuff is to elucidate the truth of both style boxes. I got tired of reading bull statements dissing Orton's slants along with his book, now in it's tenth edition. Also most younger masons today are actually believing all this snake oil rhetoric as fireplace gospel. 

And I figured as I'm just a voice of experience and not for profit, some facts would be appreciated.

Perhaps you guys will one day be called upon to build the orton and remember the book, The Forgotten Art OF Building a Good Fireplace and
remember my testimonial.

Since the book came out I was instrumental in getting his style popularized with inspectors and architects from Newhaven to Westchester. and n- west as far a Hartford, Litchfeild, Danbury so 
maybe I'm venting a bit,.. but they started in the 80's.


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## Tscarborough

I just bought it, looks like an interesting book.


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## dom-mas

Fancis Casini said:


> The only reason I post this stuff is to elucidate the truth of both style boxes. I got tired of reading bull statements dissing Orton's slants along with his book, now in it's tenth edition. Also most younger masons today are actually believing all this snake oil rhetoric as fireplace gospel.
> 
> 
> Perhaps you guys will one day be called upon to build the orton and remember the book, The Forgotten Art OF Building a Good Fireplace and
> remember my testimonial.


After reading your post and looking up what an Orton FP was I believe that I built one 7 or 8 years ago. It was a design in a book that my old partner had and was called a rumford even though it had the rolled back. It was much shallower and had more splay than a traditional FP but was deeper than a rumford and had the slanted back. We used it because the FP was only 28" wide and so a rumford would have only been 8 or 10" deep, not enough for log and not even enough to pass code. When we built it it drew very well and we heard from the home owner a couple years later that the tiny little fireplace threw so much heat that he had to open windows in the winter because it got too hot with the fireplace roaring, and it never smoked even when the fire had died down.


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## JBM

Im not really sure what your point is, that there is a slanted back way to build a Rumford, so what? It makes more heat? Ok, says you. It draws better? Better then what? Or is your point that you defied the Rumford plan and altered the design and it still worked? Who cares? 

At the end of the day if someone requested me to build that I would probably turn them down. Why? Because it simply doesnt achieve anything that a straight back Rumford can do, it would take me longer to build, and I dont think it looks any better.

In todays codes a fresh air inlet is required, have you tested it with that?

Judging from the space at the top of the firebox I would be interested to know how you achieved your 8" in the throat area? I am sure you did it, but it would be far easier to achieve this with a traditional Superior Clay throat. So why fight city hall....From what I can gather the damper is pretty snug up against the front of the face, it doesnt leave an additional 4" space like say a vestal poker damper would. Or like you said, is this firebox best used for an interior chimney where you wouldnt be in a rush to achieve your 8" to meet code.


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## dom-mas

I think that the benefit of the "Orton" is that it is deeper than a rumford. Code (at least mine) says that a FP must be at least 12" deep. Personally I think that a minimum of 14" is more desirable because in a shallower box you have to lean the logs against the back and when they collapse the ashes fall out onto the hearth. Also i think that Frank Casini is saying that a lazy fire will smoke less in an Orton than a Rumford since the rolled back brings the throat closer to the front. I can't make a comment on this personally since I don't build near enough fireplaces. In fact I'll be building one this spring for the first time in about 5 years (except that outdoor one I built last spring)


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## Fancis Casini

*we'll see who cares?*

I posted a similar post this morning at my face book site. I'm amazed with the 6 hr fire I had last night while the damper was set at 2''. I have had the damper at 1-3/4'' just once in my first video [short one] and although there was no visual smoke, it did emit an odor after a few hours. Last nights 96 sq inch throat area was great and I don't know why I skipped straight to 2-3/4'' a few years back when I was hashing with Buckley.
This setting amounts to 1/25 of the 50" x 48 1/2'' opening = 2400 sq.inch-s and amounts to a big reduction to the 1/17 to 1/20 ratio, that the straights so proudly boast. Both Buckley store dampers for a 48'' straight is 5'' x 27.5'' at 137.5sq.inch-s and as I'm sure they are not chokable [flat dampers] that's 1/16.5 ratio.
The intensity of the draft intensifies so much as the blade is closed actually enabling further closing...keep in mind there is no breast rounding or parging at all in this f p. 
Kudos for the integrals of a well made interior Orton and the proper damper which enables it less any turbulence! 

I'll do an explicit video soon showing this with fires of different intensities, and I feel the ramifications and benefits are evident. 

This is what I should have been doing years back but I was too busy wearing out trowels.
Perhaps I'll patent them for parging!.....Buckley liked my idea for niche tools, "Granfather's Mason Tools", I told him. He said to me "I don't have the time to go to flea markets"...lol


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## Tscarborough

OK, i read the pamphlet. He makes some good points and some that are against what I have learned, but he makes a strong case for them.

I have observed a (horizontal) circulatory pattern in an oven similar to what he describes in a chimney, but I am not convinced that the same principle applies in a vertical application of the length of a chimney.

That is to say, he presumes that cold air is drawn from the top of the flue stack down the backside (of the flue) and mixed with the ascending air in the front of the flue, and this is the purpose for a smoke shelf.

It is certain that a roll of air forms in that position, but I have seen nothing to lead me to believe that air enters and descends from the top of the flue to contribute to the roll of air, or if it would even matter if it did.

He also draws the front of the throat as an angle not an arch, which may just be simplicity on his part, although I consider this feature to be critical to the Rumford design as it creates a venturi effect at the level of the damper.

I will grant that a sloped back is preferable, but not that it is necessary.

Overall it is a "book" (it is only about 60 pages) that anyone who designs or builds fireplaces should read. I wish I could afford to print and send copies to every architect in the US.


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## cdkyle

My question is, are the rumford design primarily for indoor use?

I am planning to build an outdoor unit at home for myself. I like the look of the rumford's taller opening and think it would be cool to do something a little different. But, it appears to me as previously mentioned, the depth of the firebox is much smaller and is going to limit the number or size of logs one may burn.

I have seen a few rumfords, but all in older homes. There are very few actual fireboxes even built in this part of the country. Most now are zero clearance metal units.

What do ya think would be good for an outdoor firebox, rumford or orton? I built many of the or tons over the years, but never a rumford.

Great topic, btw.


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## Tscarborough

There is no difference between a Rumford or Orton, they are the same thing. Orton is merely restating the design features of a Rumford design, and attempting to (briefly) explain their merits.

Indoor or outdoors makes no difference, other than including a damper, it will work in both instances.


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## JBM

I had an exterior chimney with a Rumford and it was excellent. If you look at the drawings on the rumford.com site it shows the depth to be 14" on a 36" opening. That doesnt allow for a face brick or stone veneer. It is a rough block number. 

so when I build a rumford it is 18" as apposed to the standard 20" sqatty boxes that are standard. 

That 2" does make all the difference in the world though, it makes the side walls much more pronounced, the back wall smaller.

Of coarse I did used to start my fires in a tee pee fashion. I was under the impression(of coarse this is correct) ,that the higher you could get the flame on a tall opening like the Rumford, the more you could utilize the radiant heat of the firebox. It wasnt because people were to retarded to know how to make wood smaller to fit intelligently. After an hour or so though, only an occasional log could be thrown on, it was too hot to sit within 10' of if it was roaring.

Regarding interior or exterior I dont think it would matter. 

I personally would not use the damper they are sending out right now. They made a modification to keep the door from dropping down by adding a hook for the handle mounted between the throat and last firebrick. With the handle in the hooky thing, the opening isnt plumb, open, and a direct outlet. It is at a less the 45' angle, about 3-4" and opens directly to the wall of the throat system.(I called Superior Clay and the fella assured me this was perfectly fine)

The only way around this would be not to use the hanger gizmo for the handle and push the door open like we did for the last X amount of years. 

I will from now on use a top mount damper, run the cable down and call it a day. Unless I can get the longer old style handles.


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## Fancis Casini

*Rumford's footnote;but merely set down upon the hearth,*

The Orton is a slanted backed firebox vrs. a straight, like Rumfords' first invention ''his prototype''. 
The proto type was designed as a remedy installed into existing, thick front walled fireplaces, hence the straight backs and thicker front breast which demand rounding or risk smoke!

To function well the throat of a slant needs to be 8 or 9'' behind the face,. add a 4'' throat and a 6'' slant or so and you'll have a 19 to 20'' deep box.

Rumford did give some hint to lessening the acuteness of the side walls so as to receive longer rear logs.This is a nice option on a slant [ESPECIALLY FOR OUTSIDE] because when new logs get added they go onto the rear so the smoke gets carried up easier,...a handy trick which keeps the smokier logs at the back and up along the slanted wall and rule of thumb for all fps. 
I feel the 180 chords or so I've burned the past 30 years taught me that much.
Any idea of a heat loss do to widening the back a bit to accept a longer log is made moot due to extra heat that radiates from the slanted rear wall.
Orton suggests a back that is between 2 and 3 times smaller the front width but try and keep closer to 3. Mine is 50'' at front and 36''at back and 20'' deep. At this angle the sides still can perpendicular-ly radiate heat out into the room without hitting the opposite wall,so no loss is had what so ever, in fact the wide angle is increased! As to depth I could easily do with 18'' but years back when cooking was common place in the FP it was handy.

Buckley plays games with his fire box plans which he affixes the name True Rumford to. He shows fireboxes with true Rumford depths on one side of the F.P. jamb, then on the other he adds a face of up to 5'' which is more the Orton without a slant, but certainly not exactly a true prototype.
If you look at his 6, 7, and 8' FP plans he adds double steel lintels and a cast iron damper [lips included] and a slant the top to accomplish some added depth.There is no other bigger smoke causing error than continuing to enlarge the depth of the breast to accomplish the above, hence the need for ti pi fires.

As to placing top dampers on a straight backed Rumford fireplace I don't
think they will hurt because the dampers can't really be choked to save heat due to the fact the throats do not run the entire openings length, and the breasts are thick to boot!
But on a Orton slant, the full length damper is needed when choked small. 
Any choking at the top will be minimal and cause smoke.They can be draft inhibiting with different wind behaviors and turbulent in slow days. 
''Smoke on a rope" is what they are to me.

Perhaps when I do my 2'' choked damper video some will understand the significance of a thin long opening along a true full length throat.

I'm pondering getting Lilly my 2 year old grand daughter, to help..lol ?

Here are a couple links to straight back Rumford situtaions. One is a reply to me about the throat kit and the other is a straight burning
with smoke stained front and if you look close it's smoking slightly which is the most aggravating eddy type. Both these problems can be location caused or short chimneys I don't know.

http://www.youtube.com/watch?v=ZTQ6jdQHJN8 smoke on face

a fire in a Rumford note his reply. http://www.youtube.com/watch?v=TnDu9Wf86Vc


This is Rumford's footnote referring to his experimenting on slants.I've read this a million time and just the last time I focused on the part where he mentions it can be sat on the hearth and separate from the chimney and used in new construction!
I immediately thought about him hiring a potter and the possibility of a
entire unitized ceramic slanted firebox and throat.One that just sat there and could be moved to any? 

Any Thoughts? Could he have been aiming after the Franklin stove but with unitized masonry?....I'm positive Ben had the stove for 45 years already. 

FOOTNOTE;

[353]
Of Chimney Fire-places. When the wall of the chimney in front, measured from the upper part of the breast of the chimney to the front of the mantle, is very thin, it may happen, and especially in chimneys designed for burning wood upon the hearth, or upon dogs, that the depth of the chimney, determining according to the directions here given, may be too small.
Thus, for example, supposing the wall of the chimney in front, from the upper part of the breast of the chimney to the front of the mantle, to be only 4 inches (which is sometimes the case, particularly in rooms situated near the top of a house), in this case, if we take 4 inches for the width of the throat, this will give 8 inches only for the depth of the fireplace, which would be too little, even were coals to be burned instead of wood. - In this case I should increase the depth of the fireplace at the hearth to 12 or 13 inches, and should build the back perpendicular to the height of the top of the burning fuel (whether it be wood burned upon the hearth, or coals in a grate), and then, sloping the back by a gentle inclination forward, bring it to its proper place, that is to say, perpendicularly under the back part of the throat of the chimney. This slope (which will bring the back forward 4 or 5 inches, or just as much as the depth of the fireplace is increased), though it ought not to be too abrupt, yet it ought to be quite finished at the height of eight or ten inches above the fire, otherwise it may perhaps cause the chimney to smoke; but when it is very near the fire, the heat of the fire will enable the current of rising smoke to over-
A A 3
[354]
Of Chimney Fire-places. come the obstacle which this slope will oppose to its ascent, which it could not do so easily were the slope situated at a greater distance from the burning fuel*.
Having been obliged to carry backward the fireplace in the manner here described, in order to accommodate it to a chimney whose walls in front were remarkably thin, I was surprised to find, upon lighting the fire, that it appeared to give out more heat into the room than any fireplace I had ever constructed. This effect was quite unexpected; but the cause of it was too obvious not to be immediately discovered. The flame rising from the fire broke against the part of the back which sloped forward over the fire, and this part of the back being soon very much heated, and in consequence of its being very hot, (and when the fire burned bright it was frequently quite red-hot,) it threw off into the room a great deal of radiant heat. It is not possible that this oblique surface (the slope of the back of the fireplace) could have been heated red-hot merely by the radiant heat projected by the burning fuel; for other parts of the fireplace nearer the fire, and better situated for receiving radiant heat, were never found to be so much heated; and hence it appears that the combined heat in the current of smoke and hot vapour which rises from an open fire may be, at least in part, stopped in its passage up the chimney, changed into radiant heat, and afterwards thrown into the room. This opens a new and very interesting field for experiment, and bids fair to lead to important improvements in the construction of fireplaces. I have of late been much engaged in these investigations, and am now actually employed daily in making a variety of experiments with grates and fireplaces, upon different constructions, in the room I inhabit in the Royal Hotel in Pall Mall; and Mr. Hopkins, of Greek Street, Soho, Ironmonger to his Majesty, and Mrs. Hempel, at her Pottery at Chelsea, are both at work in their different lines of business, under my direction, in the construction of fireplaces upon a principle entirely new, and which, I flatter myself, will be found to be not only elegant and convenient, but very economical. But as I mean soon to publish a particular account of these fireplaces, with drawings and ample directions for constructing them, I shall not enlarge further on the subject in this place. It may, however, not be amiss just to mention here, that these new invented fireplaces not being fixed to the walls of the chimney, but merely set down upon the hearth, may be used in any open chimney; and that chimneys altered or constructed on the principles here recommended are particularly well adapted for receiving them


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## JBM

Well it looks as if he is repeating the same thing I am, the fireplace gets to hot. He did mention that is occasionally smokes, dunno, it might be like a family room FP. Mine only smoked when the damper would fall down...


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## Fancis Casini

*too hot ot abit*

KIDO
any Rumford gets too hot with a bonfire...that's not what we want we want heat with small amount of fire and a lot of coal bed.
The old days had fp's in each room as well as ovens in the kitchen and the basement sometimes! My neighbor has a late 1700's house with an added wing built in the early 1800's.The the older part has a 7' walk in kitchen FP with a oven and 3 other fps one on in the 2nd fl bedroom.They all angled forward like the one on the cover of the Orton's Book which went plumb a bit too far before it slanted forward.
Makes me wonder because Rumford hadn't started his Rumford work yet? These fireplaces are square and about a foot deep to 16''on the bigger one accept the kitchen which was a bout 3' deep.
In the basement there is a huge stone beehive oven that's 6' in diameter probably one of the biggest around in the country. I never could see where it drafted to but the chimney was 5 by 5' and probably rebuilt so they more than likely closed it on the 1st fl. 
Any how under the hearth of the huge kitchen FP was a stone foundation about 12 by 12' x 7' high, filled with dirt! I thought it shoddy but then I thought a bit more and figured what the heck...all that dirt and stone getting warm and being in the center of the house.....what a mass of radiant heat.They could probably shut everything down for a week and still have a house that would be in the low 60s.
I have a double set of 1775 andirons from the house,.. when the kids sold the house and had a tag sale. I think I paid 30.00 15 years ago. Funny the 1950's brass set was priced over a hundred.
About radiant heat,I designed my home so the FP was in the center.On the back side the brick wall is the dinning room wall with a small oven niche built into the back around 4'high. It is opposite the fireback and as the fireback leans forward it made room for the oven.
After I burn for about 6 hrs the back gets warm as does the side wall where there's another niche.These stay warm for days.On holidays I'll burn for 2 or 3 days straight and then everything stays very warm for about 4 days even the dinning rm floor near the brick wall. There is nothing like radiant heat as it has no on off clycles that old mason bones hate!
Bathroom mud jobs with radiant tubes are nice as are basement floors too. I have them and love it in fact last couple of years I rebuild a beach house my son bought and plumbed the kitchen and baths with infloor heat. No mud was used in the kichen I used those aluminum plates and under the plywood....nice. The plumbing gets involved but
it's a mechanics and I always loved it....had it not been for my father I'd a been a mechanical engineer......he sucked me in for cheap! lol.

u know your not far from me ...any time you want you can come and see my fp burn at the 2''. It's only 96 sq.inches on 2400 sq inch of opening......amazing vacuum stack....use the wrong damper and forget the tweaking to small gaps. IE any old hole won't do.


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## Fancis Casini

*your damper*

re;I personally would not use the damper they are sending out right now. They made a modification to keep the door from dropping down by adding a hook for the handle mounted between the throat and last firebrick. With the handle in the hooky thing, the opening isnt plumb, open, and a direct outlet. It is at a less the 45' angle, about 3-4" and opens directly to the wall of the throat system.(I called Superior Clay and the fella assured me this was perfectly fine);

Do they smoke at the 4'' or 3'' or at what opening size? They aren't built right.......either lay them at an angle by sloping the seat area. On a straight back they should hinge on the fire back wall side [like the cast irons]and at a minimum setting still be fairly open.....the problem is the throat system is built too short to choke unless under fantastic conditions with a warm and very tall chimney.
The cast throats need to be more the length of the opening and NOT THE REAR WALL? They are too far back where the narrow firebox back width dictates the short length. All they have to do is angle it forward from the opening height to the throat top....12 to 14'' Buckley has done this on his 7 or 8' fireplaces and condoned it as "works good".
Rumford frowned on any slant in the prototype only!

Many times when I use a cast damper on a slant aside from cutting the front lip off to give 4'' behind the face,I go to the next biggest length because the blades are too short and the housing is tilted in at the ends, and will cause eddys if a substantial choke is attempted.

Kinda like **** I guess...short fat dampers are worse if skinny! Put a pot belly [substitute for breast] in front and your sht outta luck! lol


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## JBM

Fancis Casini said:


> KIDO
> any Rumford gets too hot with a bonfire...that's not what we want we want heat with small amount of fire and a lot of coal bed.
> 
> u know your not far from me ...any time you want you can come and see my fp burn at the 2''. It's only 96 sq.inches on 2400 sq inch of opening......amazing vacuum stack....use the wrong damper and forget the tweaking to small gaps. IE any old hole won't do.


You are assuming that is what is required for the Rumford make the heat. It isnt, it made plenty of heat with just the coals, like you said. 

Im not really sure what your arguing. You seem to be saying that your fireplace is better then the straight back Rumford, im saying that if it is, it might not be measurable. I also think the straight back looks better then an angle, although it isnt a deal breaker either way.

Im sure you build a great fireplace, im also here to tell you that the Rumfords Buckly sells, or designed is fantastic as well. You keep coming back stating that it isnt, i think, i dunno. 

Ive only built maybe 300 or so chimneys, and only 15-20 or so of them straight back Rumfords with the kit. Im always up for better ways to do something, but it has to be better, and then it has to be faster or cheaper.


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## Mooman

I got to the end of this post where you were talking about the 1700's chimney all full of dirt and whatnot and realized you are the only person I have ever been able to chat with, that has dealt with these old behemoths besides myself. I love reading this, its like doing that project all over again. 

Anyway, so that I am not taking away from this post, here is what I would like to say....

When I started this project, it was apparent that it was ready to fall down so the decision was made to take it all down to the 4 fireboxes on the first floor. Beneath all of this was in fact this 12'x12' base full of stone and dirt which I excavated further down til I got into the beehive shaped ash dump below. No one even knew it was there or once we did, what it was. At first it was thought to be another oven. The reason for this was there were no ash dumps in any of the boxes above, plus, the channel leading down to it really did look as if it could have served as an exhaust. Once I realized that there could have been dumps in the boxes, I got the OK from the architect to further dismantle and try and discover exactly what was going on.

This was all being documented by the Historical Society so every move was cautious at the least. Turned out, the dumps had been covered or plugged some eons ago. So I ripped out the stone box floors and started over while the boxes themselves(less the bread oven) were left untouched. I later rebuilt the bread oven with a few minor improvements. The owner did not want the dumps to be visible once completed therefore presenting a problem. Operational-YES, visible-NO. So I literally whittled stones with 45 degree bottoms to hold them from falling through and created notches for fingers to get a hold to lift out when and if ever necessary. The notches were cut so that through the use of angles, could not be seen when viewed from in front of the fireplaces. 

Moving up to above the boxes, it was here where I made the decision to create my own chambers (and this is where I think some of you might cringe). I designed the smoke chambers to utilize Vestibule Dampers with 5" shelves, but, then I created spherical chambers with plum backs leading up to the first flue stack. Here, the 18" and 24" round clay tiles were set in place to continue the shape right to the top. Back down in the boxes, I wanted to reduce the turbulence it no doubt had from the many edges and cavities the original masons left due to no concern for detail. So I chiseled out all the stone from the top of the box, down about 12", and rebuilt the walls with absolutely no deviation from the vertical plane- smoothed to perfection. I then used a flap disk and smoothed and deburred the damper plates til they were perfect. I made the transition from the box walls-up through the damper and chambers, seamless. Also, much like Rumfords, I wanted to reduce turbulence as much as possible in this particular situation as I could- concerning the lintels. The existing lintels were of course massive 12' pieces of stone that spanned the entire chimney. They were of course cracked right dead center of the box openings. So I was forced to incorporate steel angle, catching 10" each side. I used an engine crane to lift the stone, then notched out the bottom(less 1" reveal to hide the steel), set the steel in place with insulation and breathed a sigh of relief it held together. 

I could go on for days, but I just wanted to share some of that experience with ya'll and point out that when your cross-sectional math is correct, and things are smooth as a mirror, a chimney, (no matter what its intended design) can pull like a freight train and throw heat to the point where you really would consider opening a window. That being said, I am fully aware that the radiant heat X pattern works best when the sides are at proper angles and the back is sloped correctly( or perfectly straight depending on what your going for). But when existing boxes meet none of these specs, and you play with the physics, you can achieve great results. This project by the way, was an outstanding success. The boxes performed flawlessly with massive heat output. All done without changing the original look and meeting all codes. 

One last thing, I have of course built traditional, Rumford, and modified fireplaces. I have seen first hand my own creations outperform all expectations. Great Post by the way. Thank you.


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## Fancis Casini

*Similar Antique Rebuilds*

Maybe that basement stone behive was a ash pit....I looked into it briefly and was going to stick bigger light into it but never did.

The neighbors had a builder whom they hired to do allot of work while I was doing the work.He was from Mass,his name was Ed Sunderland from Sunderland homes.
He was a nice guy but no mason although he thought he wrote the book on colonial F.Ps. He stuck his nose into my job when I was doing the kitchen fireplace over .He insisted the brick face firebox was original and I knew it was actually a Rumfordize attempt in front of the granite firebox.
He got the owners on his side till I went ahead and removed it and uncovered the original .....which we rebuilt sections of along with the entire throat and chamber, which had been fit with a homemade damper that was thin sheet metal and terribly wrong.

They burn the large kitchen FP allot as they sit and read and surprisingly the thing throws heat but has a large throat despite my closing it as much as possible before it'd smoke.

Here's a few pics with new plaster as was original.


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## Mooman

Fancis Casini said:


> Maybe that basement stone behive was a ash pit....I looked into it briefly and was going to stick bigger light into it but never did.
> 
> The neighbors had a builder whom they hired to do allot of work while I was doing the work.He was from Mass,his name was Ed Sunderland from Sunderland homes.
> He was a nice guy but no mason although he thought he wrote the book on colonial F.Ps. He stuck his nose into my job when I was doing the kitchen fireplace over .He insisted the brick face firebox was original and I knew it was actually a Rumfordize attempt in front of the granite firebox.
> He got the owners on his side till I went ahead and removed it and uncovered the original .....which we rebuilt sections of along with the entire throat and chamber, which had been fit with a homemade damper that was thin sheet metal and terribly wrong.
> 
> They burn the large kitchen FP allot as they sit and read and surprisingly the thing throws heat but has a large throat despite my closing it as much as possible before it'd smoke.
> 
> Here's a few pics with new plaster as was original.



Wow! Its like looking at my job. Let me see if I can dig up some photos to show you. They look so much alike. I'll go look now, not sure what I have-if any, nor what stage of the process.


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## Mooman

Alright, found some. I think the ones of everything finished up, are on another memory card and I can't find that or the thing-a-ma-jig that is needed to plug the card into the printer or whatever. But these are what you and I are talking about anyhow....


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## Mooman

Others....


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## Fancis Casini

*Oven*

Did You use a sand form for the oven or just go slow. Oven looks good they are slow and tedius. I have 3 oven niches only about 12'' and 16'' deep as I didn't have room] they are a day's work each to get the joints nice. I made trowel lines in the joints looks nice but each one has to be done as soon as it's laid.
Many old ovens weren't laid fancy but they sufficed.

So you made all round passages[smaller flues] from the chambers of the various fireboxes leading into one big flue pipe?...it's hard to tell from the pics.

You work alone ..yes?

by the way nice dogs!.....love labs and retrievers


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## Mooman

Fancis Casini said:


> Did You use a sand form for the oven or just go slow. Oven looks good.
> So you made all round passages[smaller flues] from the chambers of the various fireboxes leading into one big flue pipe?...it's hard to tell from the pics.
> You work alone ..yes?
> by the way nice dogs!.....love labs and retrievers


Yes I did use sand(exactly 18 pails worth). And thank you, I was concerned that even though the oven looks 100 times better than it was, that it didn't look good enough. Never had feedback on that one to this day.
Either 2 - 18", or (15" I forget which)- round flue and 1 - 24" round flue were used to vent the 3 boxes. And for the bread oven, I used the 4" x 8" flue to vent it. I covered the dome with multiple layers, including 2 separate layers of insulation mortar before building supports for a cap to start building again on top of that. 
All flue run right to the very top of the chimney with alternating termination points from one another above the wash. I am enclosing a photo of this shot(which happens to be in another post of mine), which clearly shows what you are asking.
Yes, I am the only employee of AJM, however, when its necessary to have help, I have another stone mason, who happens to be my ex-stepfather, help me-who is capable of some really nice work. Also, a tile guy, buddy of ours fills in as tender. I have hired guys in the past, but they didn't last long because they couldn't wrap their heads around "Quality". They just couldn't come even close to what I expect, so down the road they went. 
Last, our 3 dogs....Red and Jackson(pure breed Black Labs) Brothers and quite the clowns. They are going to be 7 this year. That leaves Lola. She is our 3 year old Bull Mastiff/lab mix and is our little huggy bear! She is the worlds sweetest dog. Can't get enough attention.


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## Fancis Casini

*heat and heat loss*

re; You are assuming that is what is required for the Rumford make the heat. It isnt, it made plenty of heat with just the coals, like you said. 

No you are thick! The radiation isn't all ther is!.. you are using a buckley designed throat situated at the extreme rear of your firebox. I think you said you had a 36'' rumford so that means your non chokeable precast throat is 4'' by 20'' long = 80sq.inchs
36x36''=1296sq inchs divided by 80 is 16.2.....you are 1/16 the opening...which means that rear throat is sucking alot of heat from the house.You may be toasty on one side but there is ice in your toilet.
This is opposite what Buckley has been saying about Ortons for some 30 years. Do you realize your un choked throat on a 36'' is 80sq inches and mine on a 50'' is 96sq.inches.That is just 16 square inches or 4'' by 4''.

You have a flat damper?.....as buckley promotes? This is because they already tested the precast throat design at 4'' and any less would be smoke prone. 
This is what Jim had written to me years back when he said my throat was double his! That statement was the catalyst for my experimenting with my damper.

Have you ever bothered to try and choke any of your straights ???

Key point here is, all the sales pitch about breast rounding is an antique practice that "had to be incorporated by Rumford to get the smoke in past those THICK breasted EXISTING fireplaces".

Why in heck should anyone want to go back in time and have a thick breast to ROUND in efforts to aid a short and a rear positioned throat THAT NEEDS TO BE MADE DEEPER.. 4'' TO 5-1/2'' and bigger, and fitted with non adjustable type dampers. For looks??? The thicker, shorter, to the rear throat is a dead givaway where the problem lies! Yes they are easy builds, just read the advertisments ....they are aimed at a less skill demanding market as well as less labor. This doesn't bode well for our trade, it's already minimal. 

Next superior should reread Rumford's footnote and do a unitized slant back[Orton] and get with the program!....but they also need to get a damper right because you can't cast 2'' throats. Access and draft variables inhibit a fixed small size. 

Meanwhile The day I see a precast throat [the current style] sitting atop a straight back Rumford with a choked throat that equals 1/25 the opening, and burning smokeless for hours upon hours, and in any type weather, as mine does, I'll agree that both styles are close..although I do agree with Rumford and like watching the fire coming up the back of a extremely hot slant, and can't see cutting logs so short for the back.

Buckley is more than welcome to show his stuff to me and I'll do mine...heck I'm doing mine anyways amost nightly...In fact I will try for 1-3/4'' which will be close to 1/30th the opening of 2400 sq inches.

I would just want equal fuels burnt and chimney lengths....because the last time I talked to him he said he was burning Fir.....which is very hot and fast burning creating a force fire.[not fair]
In fact a horizontal fire would be unsisted on for both.

By the way last night at my son's house on the sound the wind was in the 60 to 70 mile an hour range.He had the FP going and it was eddying smoke.It's a 36'' very slight slant on an exterior wall [no where elas to put it].
It has a cut vestal because I didn't want to take a day and fab one of mine [should have] but it works fine on other days so I thought about the attic and the ridge vents sucking the house negative.It helped to block the attic door bottom but it was still happening.
When I did his chimney I puposely built the outside brick wall at the flue to retain heat, but the 12x16'' flue was never going to warm up in that very cold wind so I [Bit the bullet as Buckley would say when he slanted his 8' FP to get depth] and transformed the fire into a TI PI.
This was a first for me since I was a kid camping out....but it worked as it literally pushed it's way out despite dampening high wind and warmed the chimney.

This is testament though that almost any fireplace will work with a Ti Pi and shouldn't be judged while one is used unless it's the only fire that will ever work! In that case there's a problem with the integrals and a false sense of security is being displayed or enjoyed!

I read somewhere Buckley stating, If a cold chimney doesn't draw something's not right.......The only thing I could think of now is that the Ti Pi fell down!


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## JBM

Fancis Casini said:


> Have you ever bothered to try and choke any of your straights ???
> 
> Key point here is, all the sales pitch about breast rounding is an antique practice that "had to be incorporated by Rumford to get the smoke in past those THICK breasted EXISTING fireplaces".


I really dont know what the difference is, aside from the height of the firebrick, what the difference is between this fireplace and the normal ones I build. It looks like the firebrick top opening is about 12, 12 1/2 inches. My standard opening is 14, for the vestal. Why didnt you use a 44" damper? You wouldnt have had to corbel like that.










Again, im not sure what we are speaking about, maybe you have it choked down above the damper? Im not sure, it has to fit the bottom of the flue. So regardless of the damper opening, there is a specific velocity number that is required to remove a certain amount of "smoke". To achieve the reqiured amount of velocity is going to be the same I would assume, the same based on the same amount of BTUs generated by the fire. 

So heatloss is going to be relative to the amount of draw needed, based on the size of the fire. 

Or are you saying you achieve a different velocity of draw (LESS), yet your fireplaces dont puff smoke?


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## Fancis Casini

*Or are you saying you achieve a different velocity of draw (LESS), yet your fireplace*

That damper cut measures 10'' from the fire brick jamb to the firebrick back top of wall. It is an inverted 3 1/2'' L iron on there,.. add the cast frame and its about 5'' to the throat from the jamb,..add 4'' for the brick face and it's 9'' face to throat! I usually do 8'' but a 2nd fl hall was causing a chamber reversal so I kept to a minimum the back wall tilt. Normal when tight framing is involved.

I have posted previously about widening the upper side walls to accommodate a throat that is full length....not the damper housing as you do.
The housing throat length is short the opening by alot and it's compound angled! 

You may think I'm excessive but not when it can close to a smaller
area-ed throat. And if the chimney is sluggish it prevents lazy corner draft at each end of the inner breast.....a common place for puffs, as you call them.

The chamber closes the side to flue size but gradually. These cast-irons do the job but not nearly like my damper..that is unbelievably efficient at small settings less any turbulence.The cast would never get there it's built wrong....Is it just that I have a well built slant in a perfect draft assisting scenario well..
I do have a 36'' slant in the basement with a cut off cast iron damper.
I never installed the face on it but I could put a piece of dura rock on it and test the damper's limits with a fire. I'll do this after the video.

You'll hear claims that a long throat is not as good of a clean burner like the short deep straights, but I find the smoke mostly stays where the flame is anyhow...example, if you look up at each end of the inside breast wall at my fireplace, the brick and angle iron lintel are like new even after 18 years of very frequent use..... Does my fabricated damper extend past the opening? and do my upper side walls corbel out?. No not needed.

About any minimum throat opening per calculated theory? Rumford gave his throat dimensions per testing with a straight back and it's shorter throat positioned at the rear. 
He found that 4'' was averaged to be best for most size F Ps but an increase to 5 or 6'' could be used on deep larger lodge fireplaces. 
I think he also said 3'' could be used on very small F Ps. So much for theory....it becomes apparent to use what works less any smoke but try to keep it small as possible.
I can't imagine having a fireplace without an adjustable damper because some people have a perfect scenario to take advantage of it. 
A flat damper atop those precast throats can't be choked well if at all, so some fireplaces will never be in tune.

All that inverted carburetor talk, fitted without a good draft governor,
why. 

Re your statement;
''Or are you saying you achieve a different velocity of draw (LESS), yet your fireplaces dont puff smoke?'' 

Define velocity per a fireplace function. This is not a boiler! And what I achieved is a 1 to 25 ratio on a 50'' by 48'' high slanted [Orton] Rumford.

Now as to you are talking velocity. 

It is understood that a draft coming through a thinner longer port will have stronger force [velocity] than a larger port.

A 1/25 ratio proves it is advantageous to keep this choked thin port and all it's suction/velocity as close [vertically over] where the two incoming currents are, "up close and along the entire front inner 8 or 9'' breast wall".
The natural attribute of a full length throat formed when a firebox rear wall is leaned forward has to my knowledge never been pushed to it's limits. we'll see soon

that's all


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## JBM

Since this thread is about making a traditional Rumford without the pre made throat, I thought some of the members would find this post on facebook interesting. And for those who have a passion for well built fireplaces, and Rumfords, buckley is on twitter and facebook now. 

Anyhow this fellow in Turkey made a pretty decent Rumford by hand. 
https://www.facebook.com/media/set/?set=a.10150895205694271.436635.634519270&type=3&l=5e8de87d0a


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## Fancis Casini

*Rosin experiments on fierplaces and fuel*

http://heatkit.com/docs/rosin.PDF

multiple reads needed. 

This is a very in depth group of tests done with water/dye and salt.
It was to done in a upside down model F.P. of that bedroom slant that Rumford depicted in his footnote.

It shows two kinds of eddys that plague FPs.,the breast and the smoke shelf type. They attribute The Rumford success with the 4'' throat and the rounded breast.They also say that Rumford had a hard time with down drafts coming down the rear of those big chimneys and overcame it with the narrow throat....and in the process he ended up with a shelf at the back which he stressed keeping it flat and not trumpet like as to accept downdrafts.They also give merit to a FP getting air from those stratified currents coning down the back and into the throat when the room is tight....which will enter the room if the throat is too big and not positioned right.

They explain that although this test was not done with thermo dynamics it was proper and similar enough in physics to be right.

It was designed to show air currents effects on fuel consumption
but had to address all the FP mechanics.

I looked at Buckleys sight [as I remembered reading some of this before] 
and he has this listed and wrote it off as a fluke experiment tha falsely credits Rumford with the slant variation [although he said a Rosin isn't a bad FP] an labeled "competitive propaganda" the assumption that Rumford believed in bi directional air flow in a chimney...and the use of the smoke shelf in defending against it. 
He also said a Rosin FP is shorter....which is moot as I'm concerned.

I noticed only, that the throat didn't go 3 to 6 '' past the verticle part of the inner breast. I believe this model was after the bedroom fp which was small and only 13'' deep....so Buckley is out of line again saying it was only 27'' tall...which was about what thATbedroom FP was.

Buckley; http://www.rumford.com/Rosin.html

This bi directional air "weather constant or intermittent is a reality in my book and plays havoc on weaker chimneys with large flues. The strong ones recycle it along with heat coming in from the fire.

Personally I think these new FPs with no shelf will fail unless constant makeup air and a strong draft is the norm...good luck.

The past 4 nights I pushed the envelope a bit and closed my damper to 1-3/4'' which is now 1/30 the opening.....raining now windy the other night...works great still!....video next Sat. with my son and maybe the little one?..lol 

JB you might be getting to me.. I now am starting my fires Ti Pi style!


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## JBM

You are a wealth of knowledge Francis. How does the saying go, what is old becomes new again. - and there is nothing new under the sun. I am intrigued at the size of your damper opening. It must have quite the draw to it!

I used to only start the fire as a tee pee, once it burned down i would just add a log or 2. I do remember often a log or the end of one would be out on the actual hearth, the depth of the firebox was 18" with nothing in the front. The smoke would be pulled in and go right up the clay throat.


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## Tscarborough

The Orton fireplace book led me to "The forgotten art of building and using a Brick bake oven". I just got it and haven't had time to do more than look at the pictures, but it looks interesting.


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## Joasis

Great...another book to buy, and I haven't even started my pizza oven yet.


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## Joasis

By the way Tscar....I don't suppose you have any plans on building a brick smoker, with indirect firebox?


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## dom-mas

Joasis said:


> By the way Tscar....I don't suppose you have any plans on building a brick smoker, with indirect firebox?


There are a few builds on youtube. I want to build one but I don't have the property at home to do one.


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## Tscarborough

I have thoughts, but no plans. I would like a cold smoker though.


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## Fancis Casini

*interesting questions/answers on Rumfords*

http://www.inspectorsjournal.com/forum/topic.asp?TOPIC_ID=2603


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## Mooman

So, all in all, was this particular section of Thompsons/Buckleys text, the most intriguing part for you FC?.....

"Thus, for example, supposing the wall of the chimney in front, from the upper part of the breast of the chimney to the front of the mantle, to be only 4 inches (which is sometimes the case, particularly in rooms situated near the top of a house), in this case, if we take 4 inches for the width of the throat, this will give 8 inches only for the depth of the fireplace, which would be too little, even were coals to be burned instead of wood. - In this case I should increase the depth of the fireplace at the hearth to 12 or 13 inches, and should build the back perpendicular to the height of the top of the burning fuel (whether it be wood burned upon the hearth, or coals in a grate), and then, sloping the back by a gentle inclination forward, bring it to its proper place, that is to say, perpendicularly under the back part of the throat of the chimney. This slope (which will bring the back forward 4 or 5 inches, or just as much as the depth of the fireplace is increased), though it ought not to be too abrupt, yet it ought to be quite finished at the height of eight or ten inches above the fire, otherwise it may perhaps cause the chimney to smoke; but when it is very near the fire, the heat of the fire will enable the current of rising smoke to over-
come the obstacle which this slope will oppose to its ascent, which it could not do so easily were the slope situated at a greater distance from the burning fuel*.

* Having been obliged to carry backward the fireplace in the manner here described, in order to accommodate it to a chimney whose walls in front were remarkably thin, I was surprised to find, upon lighting the fire, that it appeared to give out more heat into the room than any fireplace I had ever constructed. This effect was quite unexpected; but the cause of it was too obvious not to be immediately discovered. The flame rising from the fire broke against the part of the back which sloped forward over the fire, and this part of the back being soon very much heated, and in consequence of its being very hot, (and when the fire burned bright it was frequently quite red-hot,) it threw off into the room a great deal of radiant heat. It is not possible that this oblique surface (the slope of the back of the fireplace) could have been heated red-hot merely by the radiant heat projected by the burning fuel; for other parts of the fireplace nearer the fire, and better situated for receiving radiant heat, were never found to be so much heated; and hence it appears that the combined heat in the current of smoke and hot vapour which rises from an open fire may be, at least in part, stopped in its passage up the chimney, changed into radiant heat, and afterwards thrown into the room. This opens a new and very interesting field for experiment, and bids fair to lead to important improvements in the construction of fireplaces."

Because it certainly was for me!


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## Fancis Casini

*that's the footnote / welcome to the Orton Wells "War of the Rumfords''*

Buckley is in denial that this slant experiment is where Rumford was headed.....he writes it off as a "nice try" but a failure due to smoke and large throats!

The Rosin and the Orton are derrived from Rumford's little bedroom
slant.

Read my last post ...the experiment model was basically his bedroom.They substituted different dimentions foe each experiment to see different results.

Rumford's bedroom fp is fig.7 and the Rosin invention was;38 The Rosin has no shelf as he believed they caused eddys but they are slanted and have rouded breast just. Personally I don't like Rosins.I think if he had a shelf theyed smoke because of the low throat being so close to the opening.I could just imaging a wind change causing a draft pause 
.....the smoke would have to go out in the room, I would bet.
Also I think they are all low around 27''......it's no wonder a insurance to keep from smoking without having the throat up 14'' or so above the opening. They would through heat out at that lintel height throat though!....but forget choking them!. I wonder what the throat to opening ratio is? I think it's a 4'' throat.


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## Mooman

Isn't the point here...that Ben figured out through experimentation- pretty much all that is needed to know? And that everyone that has screwed with these designs since, has not improved upon them? I mean, if even Ben himself thought that there was some improvement in creating a "slight" slant, but not to much, shouldn't we be moving away from the straight backs anyway? I mean, code doesn't really help us when it comes to "Rumford" design anyway! I don't mean building slants like they are now, just a variation between the two. Also, if one should be able to drop a plum-bob down the center of the flue and hit the center of the box, (and modern code really doesn't provide a means of easily achieving that), shouldn't we be combining the two designs to find a happy medium that works? Bens findings on angles and dimensions, seem concrete. 135 on covings, 3.5"-4" wide throat @ 12", backs @ 1/3 the openings and so on....They all work! Simple.


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## Fancis Casini

*Ben?*

By saying Ben You mean Count Rumford ? not Franklin

Both Ortons and straights work well..I really don't like mixing though, and with using the sectioned clay breasts that are 10'' deep and 8'' for the throat and face that's 18''. A 6'' slant added will get you 24''deep but it'll smoke because the throat is short of the opening by being 14'' back 4''face and 10 precast. So the burden is on the rear positioned short throat to keep the smoke from collecting along the inner breast wall . Especially at each end. 

The plumb bob from the center of the throat to the center of the box floor is basically a governor for controlling too deep a box.

8'' face and rough = 2'' to throat center = 10''....= 1/2 of a 20'' deep box. [I never realized my throat is only 7'' in from the face.]

I find 20'' is a bit too deep unless one has to cook on it...16 to 18'' is good all around . The flue inside wall is even to the throat's inside edge at 8 to 9'' back from the face. 
Try not to place a flue where it has two shelfs, in front and behind the throat...turbulence causing....Buckley says not so, but I say yes, esp on sluggish chimneys.

Start the slant at 8'' from the floor.....it helps lessen the pitch and eliminates low box turbulence....smoke and heat will then follow that rear wall with ease.........as long as you keep the fire against it new logs at the back then on top. 

I have mine going now in the rain and fog at 1-1/2'' =1/30 face to throat ratio...no smoke gotta be about 40 hours of burning so far.

I keep thinking of that footnote and the part where he says it will be able to sit on any hearth unattached! He certainly was inspired by Franklin..even with fireplaces!


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## Joe in Canada

Moderators if you could remove my post ..that would be appreciated ..didn't mean to offend.


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## JBM

Lmao hes wondering if a smaller opening will still


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## Joe in Canada

You sound bitter. I'm just working on my own place ..relax. Good thing your going to get your $2000 check in the mail..sounds like you're probably out of work


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## Tinstaafl

Joe, as a new kid on the block, you're not really entitled to a lot of leeway with a first post like that. We're easier with folks who've established themselves here and then ask a question outside of their field (essentially a DIY question). You can probably get a pretty good feel for what you want to do simply by going to Rumford Fireplaces and looking at the info there.


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## Joe in Canada

Tinstaafl said:


> Joe, as a new kid on the block, you're not really entitled to a lot of leeway with a first post like that. We're easier with folks who've established themselves here and then ask a question outside of their field (essentially a DIY question). You can probably get a pretty good feel for what you want to do simply by going to Rumford Fireplaces and looking at the info there.


I get it ..thanks. wrong place.


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## JBM

Rumford.com email Jim buckly, hes the head Rumford guy in the states.


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## Joe in Canada

Yea I figured it out. Thanks .Go back to your drinking.


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## JBM

Looks good, what flooring is going down?


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