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Author Topic: Help with 6-1-1-1 mortar!  (Read 1398 times)

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Offline Tscarborough

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Re: Help with 6-1-1-1 mortar!
« Reply #20 on: April 03, 2018, 06:50:01 PM »
Is the portland 6 months old?

Offline BANTAR1000

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Re: Help with 6-1-1-1 mortar!
« Reply #21 on: April 03, 2018, 07:02:18 PM »
Probably a little more.  I bought it in June of 2017.    Is that really an issue?  Never thought of that!

*It's been in a dry closed shed ever since the day I bought it and there doesn't seem to be any hard places or little pebbles built up. 
« Last Edit: April 03, 2018, 07:06:25 PM by BANTAR1000 »

Offline Tscarborough

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Re: Help with 6-1-1-1 mortar!
« Reply #22 on: April 04, 2018, 06:57:12 PM »
It is hygroscopic and will absorb moisture from the air.  It will usually only ball up from very high humidity or actual moisture.  Normally, if it sits in our warehouse for 3 months it is trash.  It never does (usually not 3 days), of course, but I have had some specialty ones do so.

Offline BANTAR1000

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Re: Help with 6-1-1-1 mortar!
« Reply #23 on: April 04, 2018, 08:12:24 PM »
And you don't see anything wrong with anything else I'm doing wrong?  I may go pick up another bag of portland this weekend to try. 

Offline vtsteve

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Re: Help with 6-1-1-1 mortar!
« Reply #24 on: April 05, 2018, 01:14:59 AM »
When I used some of this mix in my build, I combined all the dry ingredients and mixed *very* well before wetting it down. I don't know the best way to mix it with the lime as putty vs. dry powder... but I think you need to mix more.


In the first "My Brick Mortar" video, when you're crumbling up the pieces ~12 seconds in, it looks like there's a chunk of unmixed lime that leaves a pile of white powder on top of the loose sand. When you're saying "turns into dust" it looks like you're crushing another piece of lime, it's pure white.


Tom, did you watch this other video he posted? The last pieces that he knocked apart looked pretty decent for a day's cure. Isn't the portland just a gauging additive in this mix?

So I went out and checked on my tests this morning.  I picked up the bag of mortar and water and it crumbled from me just picking it up.  Then I started videoing.  Everything Crumbled and came apart.  Here's the vid:


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Offline vtsteve

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Re: Help with 6-1-1-1 mortar!
« Reply #25 on: April 05, 2018, 12:04:49 PM »
After looking closely at your lime bag photo (https://www.pizzamaking.com/forum/index.php?topic=47629.msg499351#msg499351) and reading this FAQ: https://www.lime.org/about-us/faqs/, I don't think you've got the right lime. Your bag refers to its contents as "limestone", which needs to be burnt and hydrated for use as mortar.

The pertinent quote:
Quote
Q:  Is aglime the same as lime?
A:  The term agricultural lime, or "aglime," usually refers to crushed limestone.  Limestone (calcium carbonate) is not the same as hydrated lime (calcium hydroxide).

You've got a bucket of wet, ground limestone, not a proper lime putty.

The mortar works -- get the right lime and you should be fine. I didn't make putty first (and I don't think anyone else on the Forno Bravo forum did, either). Scoop a batch-sized quantity of your dry ingredients, mix them well, and add water to get a workable consistency.
« Last Edit: April 05, 2018, 12:13:34 PM by vtsteve »
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Offline BANTAR1000

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Re: Help with 6-1-1-1 mortar!
« Reply #26 on: April 05, 2018, 12:14:10 PM »
I FINALLY found a store that sells Ďmasonry hydrated lime!í Itís just over an hour away. Itís not expensive, $13.5 a bag.  So itís still worth it to try this mix and not buy heat stop at $104 a bag! 

When you say to mix it more, I think Iím gonna go buy a drill bit mixer.  Roughly how long would you mix it dry,  then wet?  5 minutes and 5 minutes?

Another thing.  The mix I found on the forno bravo site say 3 parts sand.  I read Toms comment about sand amounts not being the most important for the mortar but why do you use 6 parts?  THANK YOU Steve!

Offline vtsteve

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Re: Help with 6-1-1-1 mortar!
« Reply #27 on: April 05, 2018, 12:44:34 PM »
No drill mixer needed.

To mix the dry ingredients, just pile them on a piece of plywood, then scoop up some with your trowel and plop it on top of the pile. Keep scooping/plopping until the color is even (...or just do it all in the bucket in small batches).

With some of the dry mix in a pail, pour in some water, stir, add more water as needed, scoop/plop/scrape sides until the *texture* is even. If the sand is dry, you can mix a goodly batch of the dry mix, but only wet down a small amount at a time (what you can use in a half hour) -- it doesn't take long to make more mud when the dry is measured/mixed.

Another thing.  The mix I found on the forno bravo site say 3 parts sand.  I read Toms comment about sand amounts not being the most important for the mortar but why do you use 6 parts?

Short answer: sand doesn't shrink. At 6-1-1-1, you've basically got two parts sand to one part sticky-but-shrinks.

A mixing video:

Here's another take on the mortar: http://www.traditionaloven.com/building/details/refractorymortar.shtml
« Last Edit: April 05, 2018, 12:51:30 PM by vtsteve »
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Offline BANTAR1000

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Re: Help with 6-1-1-1 mortar!
« Reply #28 on: April 05, 2018, 01:41:48 PM »
Thanks again Steve.  Iím gonna go get some lime tomorrow and try it in the morning.  I wonít have time to do much tomorrow or Saturday.  But that should give my test pieces 48 hours to cure.  Then. SUNDAY itís on! 

I think the worst part of this whole mess, is I have a huge concrete mixer but it is a hassle to use for such small batches!  LOL. Maybe my next oven...

Offline Tscarborough

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Re: Help with 6-1-1-1 mortar!
« Reply #29 on: April 05, 2018, 02:26:05 PM »
With Type S lime you don't have to make putty, that is what it is: dried putty basically, but it does work better.  After watching the video, it looks like it was too dry and the brick sucked all the moisture out too quick.  Regardless, it will be crumbly the next day, it takes a while to fully set.

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Offline BANTAR1000

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Re: Help with 6-1-1-1 mortar!
« Reply #30 on: April 06, 2018, 02:17:48 PM »
Finally!  An hour drive but, hopefully worth it.

Offline ERASMO

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Re: Help with 6-1-1-1 mortar!
« Reply #31 on: April 06, 2018, 02:54:08 PM »
You may also want to increase the amount of portland cement in your mix.  Normally the ratio of sand to portland cement is around 4 to 1.  That six to one is very weak and when you add that fire clay and lime it just makes it weaker.

Offline Tscarborough

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Re: Help with 6-1-1-1 mortar!
« Reply #32 on: April 06, 2018, 06:57:54 PM »
Erasmo, that is factually and functionally incorrect. It is a common error, one that I see daily made by engineers and architects working on commercial, municipal, and civil projects.

Mortar is not concrete, even though the ingredients are the same or similar.  Generally speaking, with concrete, you are trying to create a product with a high compressive strength a decent flexural strength and pay no attention what-so-ever to bond strength.  Mortar, on the other hand, is designed to have AS LOW a compressive strength as is possible in congruence with the masonry units being laid, and should NEVER be higher than the units being laid.  The important physical properties for mortar are Bond strength, Flexural strength, and lastly compressive strength, but ONLY to make sure that it is less than the units being laid.

The ASTM standard that addresses mortar strength is vague on purpose, because the art of mixing mortar is incredibly variable.  The standard says, "1 part cementious material to 2-1/4 to 3 parts sand".  This allows for the wide array of different types of masonry units and cementious materials used.  For the purpose of this post, you have 2 cementious materials, Portland and Type S lime.  Thus, using the standard, for every part of cementious material, use 2-1/4 to 3 parts sand.  6-1-1-1-1.  Fire clay is mildly pozzolonic, in most cases as well.

For the same reasons, the Standards do not designate how much water should be used, it is, again, up to the weather, units being laid, and cementious materials used.

Offline wotavidone

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Re: Help with 6-1-1-1 mortar!
« Reply #33 on: April 14, 2018, 06:51:25 PM »
With regard to adhesion, I believe the stronger the mortar the weaker the bond to the brick? So a mix of 3:1:1:1 will be stronger than 6:1:1:1 but won't stick to the brick as well
Mick

Offline Tscarborough

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Re: Help with 6-1-1-1 mortar!
« Reply #34 on: April 15, 2018, 10:47:13 AM »
They are not technically related, adhesion is more related to the absorption of the units being laid than strength, but functionally you are correct.  What that means is that you could create a very strong mortar with a high bond strength, you just don't normally want to.

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Offline vtsteve

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Re: Help with 6-1-1-1 mortar!
« Reply #35 on: April 15, 2018, 12:07:30 PM »
Right, the mortar always wants to be weaker than the units, since slippage in the mortar is less of a structural issue than cracks through the bricks.


I used Heat Stop 50 refractory mortar (it sets hard as nails), and it was great to work with, but I've got some long cracks through the bricks.   >:(
It's not going anywhere, though. Should have used the home brew...
« Last Edit: April 16, 2018, 12:26:52 AM by vtsteve »
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Offline Tscarborough

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Re: Help with 6-1-1-1 mortar!
« Reply #36 on: April 16, 2018, 09:04:02 PM »
Heatstop, when used as designed, IS weaker than firebrick, that is in 1/16"-1/8" joints.  In ovens, with the much wider joints, it is really too strong.

Offline vtsteve

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Re: Help with 6-1-1-1 mortar!
« Reply #37 on: April 17, 2018, 09:48:45 AM »
I tapered all my bricks with compound angles (OCD first build :)), so the joint thickness wasn't that far off.
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Offline BANTAR1000

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Re: Help with 6-1-1-1 mortar!
« Reply #38 on: April 20, 2018, 05:21:10 PM »
Okay, take 3!   I MIXED THE CRAP out of that dry mix and the same for wet.  I think about 5 minutes each!  We shall see...  I may have made the mud a bit wet, so I put a tiny bit of sand and mixed a bit more.  I had damp bricks, so I covered them with the wet towel, then plastic, then a tarp.  I also put a chunk in the ziploc bag! 



I'm working the next few days so I'll go back and check Monday!  Keep your fingers crossed.   Thanks again for the help guys!  -John

Offline Fiorot

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Re: Help with 6-1-1-1 mortar!
« Reply #39 on: April 20, 2018, 06:01:16 PM »
I have never heard of 6-1-1-1 mortar.     3 parts or 4 parts sand  1 part portland 1/2 part lime.  And bricks do not have to be damp but you need enough water in your mix.  It doesn't to wet them before laying. It is the Lime that makes it sticky. 

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