Help with my mortar mix problem.

[Bantar1000]

I've asked another forum but I just want some more eyes on this. I'm getting frustrated! I've got my hearth built and laid the cal-sil boards then put the floor on the boards. I started to mortar my sailor course using a recipe I found from another forum.

6 Sand
1 Portland Cement
1 Part Hydrated Lime (I'm using a putty made with garden lime covered in water for 6 months)
1 Part Fire Clay

I laid my first course and mortared the sides. The next day none of the mortar stuck and it had dried away from the bricks and was really crumbly. So I was told make the mix a little thinner and soak my bricks. Making a test, I mixed a small batch mortared two bricks on top of one another, another 3 bricks together and put a little mortar in a ziploc bag. I covered all the tests with a damp towel, and two plastic sheets. The temp has been around 65 all week. 48+ hours later, the bag mix was crumbly but wet, I picked up the bricks on top of each other and the bottom fell apart, the mix was like sand, and the other test broke apart with ease. Here's a vid of what happened:

https://youtu.be/5SwdxthZ7qw

I'm also including some pics of the items I'm using just in case you see something I'm missing. I've had the portland cement since May or June of 2017 and it's been stored in a locked shed off the ground. It LOOKS to be fine??? Also is the sand too course? I bought a bag of what I was told is "play sand" from Lowes. Any input would be appreciated! Thanks!

[SableSprings]

John, sorry to see you having problems with this. The home brew mortar mix used on this forum is a 3:1:1:1 (sand/portland/lime/fireclay). The problem you are having is primarily the type of lime. You need to use hydrated lime (AKA builders or slaked lime) which is a very different product than the agricultural lime you have. Hydrated lime is not created by simply soaking ag lime...it is actually created by subjecting the base ingredients to high temperatures in a controlled & specific manner. Check with Lowes/Home Depot/Menards or some other building supply businesses. Also the extra sand will weaken the resulting mortar.

Here's a link that has a nice explanation of the differences between the types of lime and their uses.

https://www.lime.org/about-us/faqs/

As an aside, be careful using the hydrated lime...it can give you some pretty bad skin reactions. Adding water to hydrated lime will also generate heat, so it's a good idea to mix the dry ingredients of the mortar together before adding water. Plastic gloves are recommended and wash your hands with plain vinegar after working with the mortar...it will neutralize the caustic elements and keep your hands from drying out and getting sore.

Hope this helps.

[Bantar1000]

Well I bought this before seeing your post today. It says hydrated lime, but doesn't have the same calcium oxide percentages as your article mentions. So I'm assuming it's not the correct amounts?

I'm having a hard time finding the stuff at a hardware store. Lowes claims it's unavailable, and only has "Type S" mixed with portland. There's no home depot near me and the only MASONRY SUPPLY STORE "Doesn't sell Hydrated Lime anymore because of the pre mixes they have."

[SableSprings]

John, I was looking on the Internet and saw two potential sources to check for builders lime. The first is Adams Products Company 252.355-7258 just south of Greenville and Manning Landscaping and Construction 252.758-0833 just east of Greenville. Another name that's commonly used might help, try typing Mason or Masonry Lime into a search...the product description should be about building & construction not soil addition.

Even though the web site says it's currently unavailable for Lowes...at least here's a link to the product you are looking for.

https://www.lowes.com/pd/QUIKRETE-50...d-Lime/3567274

Here's the Home Depot product links...even though you don't have the store chain near you......there are quite a few stores around Raleigh.

https://www.homedepot.com/p/Quikrete...0750/206090986

https://www.homedepot.com/p/Oldcastl...0081/100350513

Hope this helps...and it's sad that even the manufacturers are apparently not being good about the labeling. You have to read the product use to make sure it's the correct stuff. I did notice that the second Home Depot link is for Oldcastle Type S Hydrated Mason Lime...same manufacturer as the last agricultural lime stuff you bought. So the manufacturer connection exists.

[Bantar1000]

Thank you! And Adams Brick company is the company that told me they don't sell hydrated lime! LOL I'll try the others today!

On Type S Lime, it says a mix of lime and Portland Cement. Will that change anything in my ratios?

[Gulf]

You are confusing Type S "mortar" and Type S Hydrated lime.

[Bantar1000]

Gulf, I thought the same thing but here’s the pic of the lime from Lowe’s that sablesprings posted. The fine print says,”properly proportioned blend of Portland Cement and hydrated type s lime.”

[SableSprings]

John, try for the Oldcastle Minute Man Type S Hydrated Masons Lime (the second Home Depot link I posted). Sorry, I did not look at the fine print on that Lime (no longer available) through Lowes. It appears that Quikrete is phasing out their "pure" hydrated lime products and that may be why you got those first comments from the Lowes folks and Adams Brick Co. regarding a switch to pre-mixes. I suspect that the caustic nature of the Hydrated Masons Lime is making some companies distance themselves from the products having potential liability issues.

[Bantar1000]

Haha WIMPS! Lol

i am going to another masonry supply store just over an hour away in the morning to buy a bag of ‘masonry hydrated lime.’ It’s probably a good situation, I’ll have time to get back and make a bunch of test bricks. I have to work tomorrow afternoon and all of Saturday. So that’ll give them 48 hours to test, and Sunday I’ll hopefully be able to go at it! Thanks again!

[Gulf]

I can't see the pic of the product description in your post. But, "properly proportioned blend of Portland Cement and hydrated type s lime" can be a description of any "old school" masonry cement. Type N masonry cement is 50% Portland cement and 50% hydrated lime. Type S masonry cement has a little more Portland in it than Type N.

[Bantar1000]

Victory! Only an hour away. This company said the only reason they stocked it, is because a high school in town teaches kids how to make mortar and cement from scratch. Keep your fingers crossed!