# Why is type S hydrated lime special



## fjn (Aug 17, 2011)

I'am sure that many of you have ran across this essay in one place or another however,for the benefit of those who have not,here it is. Enjoy!

http://buildinglime.org/Thomson_TypeS.pdf


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## CJKarl (Nov 21, 2006)

Interesting, but the technical aspects are way over my head. Can I just slake a bag of hydrated lime and get lime putty? That's all I want to know.


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## Tscarborough (Feb 25, 2006)

Yes, if you slake a bag of Type s, you will get lime putty. The difference is that you can slake it for 24 hours instead of 3 years and get an equivalent product.


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## fjn (Aug 17, 2011)

CJKarl said:


> Interesting, but the technical aspects are way over my head. Can I just slake a bag of hydrated lime and get lime putty? That's all I want to know.






Yes you can. I agree with Tscarborough,it can work in 24 hr. not 3 years.

I have found that 7 gal.to 50lb of lime works well. Lynch recommends that volume. It will produce lime "soup"however,it seems to be the correct volume of water to mix with 3-3.5 parts damp sand.


This produces a very "fat" mix and I believe it can "carry" 4 parts sand with no trouble but I do not push it and go with 3.5.



I use a large round tub and the mud paddles drywall guys use. I turn it slowly with a Hole Hawg drill. One can mix it till it has no lumps,let it sit a day and you are good to go.


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## dom-mas (Nov 26, 2011)

The putty will fatten up, (meaning that the water that makes it soupy will leave and sit on top) if left alone for a while. It should become like full fat sour cream or yoghurt. If it's watery like low fat sour cream or yoghurt it will still be fine but it won't feel like the fatter stuff. 

If you have a mortar pan, put it in the back yard and fill it 1/2 way, then put a screen on top and shake the bag of lime in slowly. Let it sit at least 24 hrs, then pour off the water on top, put the putty in pails and cover with an inch or so of water, it will keep forever as long as there is water on top


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## Diamond D. (Nov 12, 2009)

dom-mas said:


> put the putty in pails and cover with an inch or so of water, it will keep forever as long as there is water on top


Or until the bottom of the old steel spackle bucket rusts through...  ...even then you could probably bring it back, if it wasn't all rust stained. :sad:

D.


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## dom-mas (Nov 26, 2011)

Ok...or use mostly inert plastic buckets.


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## dakzaag (Jan 6, 2009)

I mortared some limestone caps onto two pillars last fall. The Library that I made the sign for wanted to put two time capsules in the pillars this summer.

I used Hydrated type S and a handful of Portland cement to make a small wheelbarrow mix. When I went back a few weeks ago to take the caps off, the mortar was flakey with out any strength at all.

The only thing I did not do is slake the type S overnite, I just used it right out of the bag with sand and portland. ratio of about 2:.25:1, sand portland and lime.

I question if we can make lime putty out of Hydrated type S lime, but I will need to conduct more tests. I am currently using a commercial Lime product to point up an old wall with the mortar crumbling out.


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## dom-mas (Nov 26, 2011)

Did the lime flash set? Did you water/mist it at all following the install? If you don't keep the lime hydrated after it will just turn to dust. I did a job last year using just bagged lime and 1/4 part portland. It rained the next day and it is also beside a river so gets a lot of humidity and some spray. Also north side and very little to no direct sun. I had to do some repair below it later that summer and had to cut out some of the joints I had done earlier in the year (first brick then the foundation). The joints felt great. Just like old mortar that I consider to still be sound. Yielding but solid. Not crumbly, but not brittle hard either. 

I've used that mix before on hot days with dry brick and without watering, or not watering enough and it was no good. Powdery dust. Lime definitely needs more tending to after installing.


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## Tscarborough (Feb 25, 2006)

The best way is to not mix the lime at all. Put it in the bucket, ease the water in so that there is 6-7" of coverage and leave it alone. Mixing it can cause lumps if you are not extremely diligent.

I used to be a proponent of gauging lime mortar with Portland up to 10%, but have since seen the studies that show that it does not help the mortar at quantities over 1%. I have tried marble dust up to 5% and it works, but the best is brick dust at 1-2%, if anything at all.


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## CarpenterSFO (Dec 12, 2012)

Tscarborough said:


> Yes, if you slake a bag of Type s, you will get lime putty. The difference is that you can slake it for 24 hours instead of 3 years and get an equivalent product.


Not even close. I have a specialty business in tadelakt and some other natural lime plasters, and we pull the occasional custom moulding with the finish layer being putty with a little plaster of paris to gauge it. When we empty a bucket of putty we make a new one - a bag of type s plus water - too much water is fine, as it settles to a perfect consistency with a pool of water on top. The ones we have that are currently ready for use are about 3 years old, and it is a completely different animal from a 24-hour or 30-day putty. More like a block of lard than anything mineral. It completely transforms any mix, including most mortars. We throw some into NHL plasters to make them plastic - just a little dab'll do ya. Plasterers used to keep big pits of the stuff, years old. It doesn't work for everyone to store a bunch of buckets of lime, but for that piece of my business, that 3-year old stuff is an asset.


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## CarpenterSFO (Dec 12, 2012)

dom-mas said:


> Did the lime flash set? Did you water/mist it at all following the install? If you don't keep the lime hydrated after it will just turn to dust. I did a job last year using just bagged lime and 1/4 part portland. It rained the next day and it is also beside a river so gets a lot of humidity and some spray. Also north side and very little to no direct sun. I had to do some repair below it later that summer and had to cut out some of the joints I had done earlier in the year (first brick then the foundation). The joints felt great. Just like old mortar that I consider to still be sound. Yielding but solid. Not crumbly, but not brittle hard either.
> 
> I've used that mix before on hot days with dry brick and without watering, or not watering enough and it was no good. Powdery dust. Lime definitely needs more tending to after installing.


All true. San Francisco's ideal for lime plasters - foggy and cold.


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## Tscarborough (Feb 25, 2006)

Obviously, it was an exaggeration, but if you are gauging with NHL you know what you are talking about.


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## CJKarl (Nov 21, 2006)

Couple years ago I build a chimney kiln and burned my own limestone. I made putty then wrapped it up tight in a trash bag. Used about a year later. Made a 3:1 mortar for some limestone. It was really nice stuff. Not plaster quality, but back yard 1st time experiment grade. Still better than ANY bag mix I ever made.


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## CJKarl (Nov 21, 2006)

Well then, time to experiment with making some bagged lime putty.


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## CarpenterSFO (Dec 12, 2012)

CJKarl said:


> Well then, time to experiment with making some bagged lime putty.


Orange HD buckets with the snap lid work great. Mix it decently with a drill mixer. Leave some extra water at the top which you use to wash everything down below the water level so you don't have dried out chippy stuff at the top. Try to leave it alone, except to make sure your buckets don't have slow leaks. Just keep it wet on top. If you want, after a year mix it up with the excess water. Don't worry about the excess, as it settles to the perfect consistency and you can pour the water off when you get around to using it. If you manage to keep any of it longer than a year you'll sample it and run out and buy a bunch of TypeS and some more buckets, and wish you'd done it earlier. That's my experience, anyway.

- Bob


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## fjn (Aug 17, 2011)

dakzaag said:


> I mortared some limestone caps onto two pillars last fall. The Library that I made the sign for wanted to put two time capsules in the pillars this summer.
> 
> I used Hydrated type S and a handful of Portland cement to make a small wheelbarrow mix. When I went back a few weeks ago to take the caps off, the mortar was flakey with out any strength at all.
> 
> ...





Several studies / authors have identified the problem created when less than 50% of the binder added to a lime mortar is used. Gauged lime mortar of a handful to less then 50% is the "death" of the lime to contribute / participate as a binder in the mortar. This was brought out by Lynch,Holmes,Wingate among others.


Also it is back to that previous thread where the age of the lime begins to carbonate in the bag from day one,by six months it is real iffy.


Shooting from the hip,that may weel have been the cause of your troubles.


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## fjn (Aug 17, 2011)

I need to clarify the term binder, meaning OPC.


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## Diamond D. (Nov 12, 2009)

CarpenterSFO said:


> putty with a little plaster of paris to gauge it.


That's how I've always done it. Maybe, throw in a little cream-of-tarter, to prolong setting. Although, on the last patch job I did, I just grabbed a bag of Diamond... No time for a long soak.



> that 3-year old stuff is an asset.


The older the better IMO, if your talkin' plasticity. :thumbup:
Of course, now I use plastic buckets.:whistling

D.


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## ArtisanRemod (Dec 25, 2012)

I have almost no masonry experience but i seem to lurk around this sub forum the most. Fascinating exchanges of info here.


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## dakzaag (Jan 6, 2009)

fjn said:


> Several studies / authors have identified the problem created when less than 50% of the binder added to a lime mortar is used. Gauged lime mortar of a handful to less then 50% is the "death" of the lime to contribute / participate as a binder in the mortar. This was brought out by Lynch,Holmes,Wingate among others.
> 
> 
> Also it is back to that previous thread where the age of the lime begins to carbonate in the bag from day one,by six months it is real iffy.
> ...


The pillars were constructed in Dec. just before Christmas in Northern Indiana, Rain set in on the last post and I had to cover with a tarp for several hours and finally rodded the joints way too wet and left it covered for the night. That was a Friday IIRC and I went back on Monday to remove the tarp and finish the clean up. I brushed the joints way too wet and smeared mortar across the Scratch face brick that you can still see today 

I am quite sure it did not flash set. The lime bag was of unknown age, I picked it up at my feed supplier (I feed a few head of cattle for our own consumption) after seeing it there for a couple of months in a row. I have no idea why he had it on hand or for how long. I know I just put a small handful of OPC in the mix and probably two shovels of lime with four shovels of sand. Just enough to set two 26" X 26" caps.

I took a diamond blade and chisels with to remove the caps, but was able to just bump with my palm and remove the caps. (actually worked like a charm as I did not want to risk breaking the caps trying to remove them, but they appeared to be solidly set with typical mortar.)

Certainly the age of the type S could have had an impact, but I am also concerned about the lack of any additive when using straight Lime. I believe a pozzoloan (sp?) is critical and OPC is not a great additive if your into restoration work. In this setting, a 50-50 mix of lime and OPC would be plenty strong, which was the last thing I wanted.

Once they call me back to recap the pillars, I am not sure what I will use as this time the life expectancy will be fifty years.


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## dakzaag (Jan 6, 2009)

On another note, I was thinking about leaving something on top of the time capsule such as my invoice or the shipping ticket. Since the library supplied the brick and I just used premix mortar on all of it but the Caps, the invoice and shipping ticket will be a little deceiving regarding the cost of construction and where the brick came from. 

Belden red scratch face. Fairly hard brick that did not suck up much water at all on the cold days we worked last winter. Once the rain set in I put a smudge bucket under the tarp to accelerate the drying, but it was a waste of time. Helper and I sat in the truck for two hours in a decent down pour watching some family have their Christmas party at the library. Once it hit 7pm I said screw it and hit the joints, brushed it off and set the smudge bucket in the middle of a catch basin nearby.

Customer never said boo about the mortar stains.:clap:


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## CarpenterSFO (Dec 12, 2012)

CJKarl said:


> Couple years ago I build a chimney kiln and burned my own limestone. I made putty then wrapped it up tight in a trash bag. Used about a year later. Made a 3:1 mortar for some limestone. It was really nice stuff. Not plaster quality, but back yard 1st time experiment grade. Still better than ANY bag mix I ever made.


I had to read that a couple times before I realized what you were saying. That is old school, seriously.


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## CarpenterSFO (Dec 12, 2012)

dakzaag said:


> The pillars were constructed in Dec. just before Christmas in Northern Indiana, Rain set in on the last post and I had to cover with a tarp for several hours and finally rodded the joints way too wet and left it covered for the night. That was a Friday IIRC and I went back on Monday to remove the tarp and finish the clean up. I brushed the joints way too wet and smeared mortar across the Scratch face brick that you can still see today
> 
> I am quite sure it did not flash set. The lime bag was of unknown age, I picked it up at my feed supplier (I feed a few head of cattle for our own consumption) after seeing it there for a couple of months in a row. I have no idea why he had it on hand or for how long. I know I just put a small handful of OPC in the mix and probably two shovels of lime with four shovels of sand. Just enough to set two 26" X 26" caps.
> 
> ...


Just random comments:

TransMineral imports some natural hydraulic limes that are widely used in the U.S. for restoration work as mortars and plasters. They're local to me, so it's easy for me to use them. Their plasters are outstanding, if expensive.

Regarding pozzolans, brick dust is one. It has to be awfully fine. White china clay is decent. Tap Plastics sells silica fume as a filler for epoxies. About $10 for a cupful. Maybe $100 for a 50lb bag. In my experience it's a good pozzolan for typeS lime - it's hard not to over-use it, though. Experiment with the cupful first if you're tempted.


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## stuart45 (Oct 7, 2009)

For internal work all the plasterers I know use lime putty at least 3 years old. 
I normally use NHL 3.5 for external pointing etc. 
Getting the mix right is really important with lime. I've got a garden wall to repoint this week and will use NHL 3.5 and a mix of sharp and building sand.
You need to leave NHL mixing for at least 20 minutes in a drum mixer.
Our local Council issued this leaflet on lime mortar, as most buildings round here have it.
http://nshistoricplaces.ca/conservation_resources/documents/limeinhistoricbuildings.pdf


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## CarpenterSFO (Dec 12, 2012)

stuart45 said:


> For internal work all the plasterers I know use lime putty at least 3 years old.
> I normally use NHL 3.5 for external pointing etc.
> Getting the mix right is really important with lime. I've got a garden wall to repoint this week and will use NHL 3.5 and a mix of sharp and building sand.
> You need to leave NHL mixing for at least 20 minutes in a drum mixer.
> ...


There's that magical 3-year number! :thumbsup: The use of NHL is much more widespread in England than in the U.S., I believe. I don't think there are any U.S. NHL makers - it's generally one of a couple brands, St. Astier and another, imported from France. At $30 per bag, it makes plasters and renders lots more expensive, and mortars somewhat more so. So NHLs get used for people who are willing to pay significantly more - green, restoration, and luxury plaster finishes such as tadelakt.


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## stuart45 (Oct 7, 2009)

$30 a bag is a lot. I thought ours was dear at between £8-£11 a bag.
NHL is used a lot round here. Our local builders merchant stocks almost as much NHL 3.5 as cement.
http://www.mikewye.co.uk/mikeprices.htm?gclid=CKnpgoqm7rcCFQTHtAodmwQA0A#hydrauliclime


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## dom-mas (Nov 26, 2011)

fjn said:


> Several studies / authors have identified the problem created when less than 50% of the binder added to a lime mortar is used. Gauged lime mortar of a handful to less then 50% is the "death" of the lime to contribute / participate as a binder in the mortar. This was brought out by Lynch,Holmes,Wingate among others.


Different studies have said different things.


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## dom-mas (Nov 26, 2011)

Ok, so the mortar definitely didn't flash set. But are you sure it was masonry lime or did you use agricultural lime? While masons lime can be used in agriculture not vice versa.

Not sure what a smudge pail is but I'm guessing it's a heater? Maybe not enough CO2 for a decent set, heater may have created CO instead


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## dakzaag (Jan 6, 2009)

dom-mas said:


> Ok, so the mortar definitely didn't flash set. But are you sure it was masonry lime or did you use agricultural lime? While masons lime can be used in agriculture not vice versa.
> 
> Not sure what a smudge pail is but I'm guessing it's a heater? Maybe not enough CO2 for a decent set, heater may have created CO instead


Hydrated type S lime. Ag lime is just finely ground up limestone. 

I have two quarries within one mile of my house that sell several thousand truckloads of ag lime every year for farm application. Pretty familiar with that product as well.

A smudge bucket is just a metal pail with wood burning in it to put off some heat and usually a lot of smoke. Old timer's recipe for cold mornings and warming up your hands on occasion. Some times we will cook lunch on it if the flame is down and plenty of hot coals. 

When I was trying to get my mortar to harden enough to strike, the tarp was draped over the pillar and then we tented one side with a stick to allow the fire to burn without rain dripping into it. (poor folks have poor ways...:whistling) While anything is possible, I highly doubt we could have drove out a majority of the oxygen with carbon monoxide from the fire. 

I suspect age was an issue and it certainly is a concern with any purchased Lime product.


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## rogerhattman (Jul 6, 2008)

I find that hydrated lime makes an acceptable putty. I like to sit type S for longer than recommended. Adding the right amount of water seems more critical. I actually prefer Graymont's type N dolomitic (Grand Prize). It is intended to be made into putty. It takes longer than S, but water amounts are less critical.

For really critical work, I prefer my hand slaked (from quicklime) years old lime putty. In spite of what the article claims, hydrated lime is not quite the same. One issue not addressed in that paper is reactivity.

I pay +50$ for St Astier NHL and am happy to have close by. To economize, I often add NHL 5 to regular putty and avoid less hydraulic NHLs.

On brick dust, be careful since modern brick and old brick are quite different.


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## CJKarl (Nov 21, 2006)

I have an almost unlimited supply of plastic barrels, (from my local block plant ) I could do a few bags at a time.


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## concretemasonry (Dec 1, 2006)

Do they come from Westbrook by any chance?


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## CJKarl (Nov 21, 2006)

concretemasonry said:


> Do they come from Westbrook by any chance?


Why yes, yes they do. :thumbsup:


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## CJKarl (Nov 21, 2006)

Heavy blue ones and lighter white ones. I think one has liquid soap for air entraining. The other had some non hazardous stuff. So no nasty surprises when washing them out.


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## CJKarl (Nov 21, 2006)

I can also get barrels form a local plant that makes antacids. Get barrels with about 1/2 gallon of peppermint oil left in them. I'll tell you peppermint oil is a good herbicide. Killed every weed in my driveway and made it smell nice for about a month. :laughing:


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## dom-mas (Nov 26, 2011)

peppermint oil is also good for sore throats i think. My wife gives me some sort of stuff anyway


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## stonecutter (May 13, 2010)

dom-mas said:


> peppermint oil is also good for sore throats i think. My wife gives me some sort of stuff anyway


So is Woodford Reserve, but the barrels are hard to get....bummer.


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## fjn (Aug 17, 2011)

rogerhattman said:


> For really critical work, I prefer my hand slaked (from quicklime) years old lime putty. In spite of what the article claims, hydrated lime is not quite the same. One issue not addressed in that paper is reactivity.
> 
> I pay +50$ for St Astier NHL and am happy to have close by. To economize, I often add NHL 5 to regular putty and avoid less hydraulic NHLs.
> 
> On brick dust, be careful since modern brick and old brick are quite different.






I believe the idea for the three aging for lime was first brought to the fore front by the Roman engineer Vitruvis. In many papers mortar was used interchangeably meaning plaster,renders, and the stuff that holds masonry units together or apart as one chooses to view it. With that said,I feel the needs of the plastering trade and masonry trade are different. Will three year old lime work for masonry? Absolutely. Is it necessary? I do not think so.

As far as brick dust pozzalons go,in a previous thread the link was provided to the current research paper by Sara B. Rogers ,written in 2011. It weighs in on that topic quite thoroughly.


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## JBM (Mar 31, 2011)

dom-mas said:


> peppermint oil is also good for sore throats i think. My wife gives me some sort of stuff anyway


I think your thinking of peppermint schnapps :laughing:


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## fjn (Aug 17, 2011)

For those interested,here is the connection for Sara's paper on pozzalons.

http://repository.upenn.edu/cgi/viewcontent.cgi?article=1178&context=hp_theses


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## stonecutter (May 13, 2010)

Thanks for that one FJN. It might break some brains at 206 pages though.:laughing:


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## fjn (Aug 17, 2011)

ArtisanRemod said:


> I have almost no masonry experience but i seem to lurk around this sub forum the most. Fascinating exchanges of info here.






I was just about to weigh in on this post when my bug-aboo computer troubles struck.

I thought to resurrect this post before it became "old". Perhaps the reason many "lurk" around this site (without discrediting other trades) is because masonry is an extremely fascinating,somewhat esoteric craft that borders on being an art form.


Some accounts of the history of the craft talk about the masons banding together and not sharing their knowledge to the non "initiated" so as to not come completely under the Kings and Church of Rome's thumb as they needed to have their castles and cathedrals built.


Many other trades have experienced a huge volume of power tools enter into their arena,whereas the masonry trade has had their upgrades, power mixers,tower scaffolding,diamond saws etc. however we as masons imho still produce some of the most beautiful,long lasting,inspiring buildings in the world with the same basic tools used for millenniums.......a simple ball of line,a hammer a plumb rule,and most importantly a trowel.

Admitting my partiality to masonry,I have to say the aforementioned reasons possibly are why many are captivated by our discussions and our final finished products.


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## dom-mas (Nov 26, 2011)

Personally i think it's the use and understanding of the uses of string that is what makes masonry so interesting. No other tool that I can think of is so versatile and true. When folks wonder how the ancients built structures that were so true without lasers or other modern tools, I think of string and math and see the answer


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## fjn (Aug 17, 2011)

dom-mas said:


> Personally i think it's the use and understanding of the uses of string that is what makes masonry so interesting.





I find your thought quite interesting ! I remember older timers jokingly saying years ago,the whole world would be out of square if not for a ball of line.:laughing:


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## dom-mas (Nov 26, 2011)

It's amazing the things you can find out with string. Making 90* angles, bisecting angles, making circles, making segments of circles, making ellipses (making ANY shape really), dividing spaces, and the list goes on and on and on. With simple string

oh yeah, you can even make things straight. In 2 directions at once if the string is tight enough


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## stonecutter (May 13, 2010)

And, string makes a good belt when you forget yours at home too.


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