# Plastering a Firebox



## JBM (Mar 31, 2011)

Doing a chimney right now and the owner wants a smooth plastered firebox. What would I do that with?


----------



## fjn (Aug 17, 2011)

About a year or so ago, New Old House magazine had an article pertaining to period looking fireplaces. The plastered / parged firebox was mentioned as a good idea. They did not get into details regarding the mix. Shooting from the hip,I would say score the brick,apply bonding agent,parge with type S. The logic of the parging in days gone by was to protect the brick ,they did not normally have firebrick as we know today. The parging was expected to be renewed periodically.


----------



## JBM (Mar 31, 2011)

What's your opinion of this?
http://store.limeworks.us/mobile/Product.aspx?ProductCode=TCOAT


----------



## Tscarborough (Feb 25, 2006)

I would only feel somewhat safe using a buildable refractory material like Heatstop.


----------



## JBM (Mar 31, 2011)

I agree. I was hoping I could get him to whitewash it but nope.


----------



## superseal (Feb 4, 2009)

Chamber-tech 2000 is designed for direct flame contact and would be a smart choice.

Lay it on thick 3/4" to 1" and you'll be pleased with the results.


----------



## JBM (Mar 31, 2011)

What color does it dry?


----------



## superseal (Feb 4, 2009)

JBM said:


> What color does it dry?


Usually light grey to buff, depends on how you juice it :whistling


----------



## JBM (Mar 31, 2011)

You use it for burned out firebox es usually? If they don't want a redo?


----------



## superseal (Feb 4, 2009)

Yes, don't be fooled thinking it's only for chambers. Important thing is to clean and wet the surface. It's a nice high build mud that goes on thick. I've plastered several old stone boxes that were hammered. It will add structural performance @1 1/2" thick if I remember right and can easily be placed much thicker than that.

You can sponge or hard trowel it as well. 

https://www.youtube.com/watch?v=YWLo_dKRSJc


----------



## JBM (Mar 31, 2011)

Do you think it will work ok @ 1/2 or 3/8"?


----------



## superseal (Feb 4, 2009)

JBM said:


> Do you think it will work ok @ 1/2 or 3/8"?


Is it new work? I would say yes to 5/8"+ just to be sure. You could always throw on a scratch and see how it feels. I might even spike it with a tad of portland since it acts like fat mud anyway :whistling


----------



## fjn (Aug 17, 2011)

My vote for product, goes to SS's idea for Chamber-Tech. :thumbsup::thumbsup:



Never used it however,it looks like the ticket.


----------



## Fancis Casini (Jan 31, 2013)

superseal said:


> Yes, don't be fooled thinking it's only for chambers. Important thing is to clean and wet the surface. It's a nice high build mud that goes on thick. I've plastered several old stone boxes that were hammered. It will add structural performance @1 1/2" thick if I remember right and can easily be placed much thicker than that.
> 
> You can sponge or hard trowel it as well.
> 
> https://www.youtube.com/watch?v=YWLo_dKRSJc


Boy have I heard this before. Years ago I had an offer to plaster a clininic in Harlem on Amsterdam Ave. It was for Quinn Const and it was the beginning of revamping Harlem. The job was to clean and plaster over heavily spalled and rusted reinforced concrete exposed beams both vert and horz between the brick face. They supplied this new stuff by ''Thouro Seal'' called ''Thorite'' It clamed similar ''pie in the sky results'' ie can be applied 1-1/2'' thick in each app, set fast etc etc and ''woudlnt shrink''. 
It was a good thing Thouro Seal people filmed me becasue it all shrunk badly.
I did it right they said so I got paid and they came up with this elastomeric masonry flex paint to hide it all!...we all know these two products well now but I'm a big skeptic that anything will work as a plaster on a firebox esp if it's heavily used! 
The heat clycling will separate it from the already bad brick imo.

Many boilers and furnaces stay hot so the hot cold thing isn't a big factor!


----------



## Tscarborough (Feb 25, 2006)

I misread, sorry.


----------



## JBM (Mar 31, 2011)

This product from heatstop says I can put it on no thinner then 1/4 - 1/2 thick. I would rather not put something on an inch thick if I can help it.

http://www.heatstoprefractorymortar.com/productDetail.php?INSUL-STICK-5


----------



## Tscarborough (Feb 25, 2006)

JBM said:


> This product from heatstop says I can put it on no thinner then 1/4 - 1/2 thick. I would rather not put something on an inch thick if I can help it.
> 
> http://www.heatstoprefractorymortar.com/productDetail.php?INSUL-STICK-5



Insulstick is Heatstop with perlite added. The thicker you need to go, add more perlite or crushed firebrick.


----------



## JBM (Mar 31, 2011)

I ordered this, 10 bucks cheaper then the chamber tech, probably the same stuff, or not. It just has to stick and be smooth eh?

http://www.amazon.com/SaverSystems-...3445601&sr=8-4&keywords=saver+systems+chamber

I didnt realize there was refectory parging products. Might incorporate them into my throats.


----------



## Tscarborough (Feb 25, 2006)

It says it can be used to parge corbeled brick smoke chambers, so it should be good from zero to inches.


----------



## superseal (Feb 4, 2009)

You'll be alright J, don't listen to that Casini character, he can't even spell Thoro right :laughing:

Just kiddin' Francis...


----------



## Fancis Casini (Jan 31, 2013)

superseal said:


> You'll be alright J, don't listen to that Casini character, he can't even spell Thoro right :laughing:
> 
> Just kiddin' Francis...


 lol it's named after a god ..or was that Thor ?????:jester:


----------



## fjn (Aug 17, 2011)

Tscarborough said:


> It says it can be used to parge corbeled brick smoke chambers, so it should be good from zero to inches.




That brings up a side shoot topic. Most codes mandate a smooth smoke chamber. I believe solid brick,not cored work better in smoke chambers.With that said,in order to provide a smooth smoke chamber,I cut the ends of corbelled brick to match the slope angle. Solid brick seem to work best in that application and require less parging.


----------



## Fancis Casini (Jan 31, 2013)

fjn said:


> That brings up a side shoot topic. Most codes mandate a smooth smoke chamber. I believe solid brick,not cored work better in smoke chambers.With that said,in order to provide a smooth smoke chamber,I cut the ends of corbelled brick to match the slope angle. Solid brick seem to work best in that application and require less parging.


I do too. The old man would show me how to cut them with the trowel heel if they werent too hard.....fast when practiced.
He'd say cut one right then use it for the example.. place it against the next brk and scratch it then cut it at the scatch line...lay it with your trowel under it at the corbel end and catch the mud and fill the bottom joint as you slide the trowel upward. I liked the pencil better...lol


----------



## Fancis Casini (Jan 31, 2013)

just an added comment...my basement fp which has the angle cuts and no parging works fine in fact it it has a cust vestal damper and does a 1:26 ratio...I see no need to parge if the brickwork is good .. it hides ham-n-egger's short cuts.


----------



## dom-mas (Nov 26, 2011)

I like the idea of cutting 2 flue liners to make a smoke chamber

What does Stuart call it...a "gather".... I like it


----------

