Heat stop premixed mortar

[clamparillo]

I am just finishing my stand on my oven build. I bought heat stop premixed mortar for the oven but I'm unsure if that's what I should be using...please give me some input if I should not be using this

Thank you

[Les]

Re: Heat stop premixed mortar

Heat stop and refmix are fantastic products when it's purchased in the dry form. We have heard that the premix doesn't perform very well. I have not used it so I really do not know. If you search the forum you may be able to dig up the old discussions.

[stonecutter]

Re: Heat stop premixed mortar

Premix is good for small batch jobs, you're better off with dry bagged or use the 3:1:1:1 component mix

[NCMan]

Re: Heat stop premixed mortar

Stonecutter.....when I start laying oven wall bricks, I will probably have to do it a little at a time. Maybe do a few bricks every evening or as my time allows. In your opinion,what would be my best solution for oven mortar? I had been planning on the homebrew/component mix (assuming they are the same thing), but that's alot of measuring, just to do a few bricks at a time. What are the pros and cons of perhaps using the Premix? I do want to watch the budget, but at the same time, looking for what'd be best if I did a small bit at a time? I did ask about prices on Heat Stop here and was told it was $110 for a 50 lb. batch, I believe it came in a bucket. I did not see it, just got the quote.

[stonecutter]

Re: Heat stop premixed mortar

Stonecutter.....when I start laying oven wall bricks, I will probably have to do it a little at a time. Maybe do a few bricks every evening or as my time allows. In your opinion,what would be my best solution for oven mortar? I had been planning on the homebrew/component mix (assuming they are the same thing), but that's alot of measuring, just to do a few bricks at a time. What are the pros and cons of perhaps using the Premix? I do want to watch the budget, but at the same time, looking for what'd be best if I did a small bit at a time? I did ask about prices on Heat Stop here and was told it was $110 for a 50 lb. batch, I believe it came in a bucket. I did not see it, just got the quote.

They are the same thing...I just don't like calling it homebrew, that term makes no sense to me as mason.

If you want to go that way..it's certainly the cheapest....why not dry mix a large batch ( your sand needs to be bone dry) then you can just scoop what you need and add water.

Water, heat and air are what activates the mortar, and who knows how long your bucket sat before you start using it. Then you are opening and closing it, until it's gone. But my main reason is that I want control over the consistency of the mortar I use.

If you have the budget, the dry bagged Heatstop 50 is a good product. Add water and go...just work fast and dampen your masonry.

[GianniFocaccia]

Re: Heat stop premixed mortar

If you want to go that way..it's certainly the cheapest....why not dry mix a large batch ( your sand needs to be bone dry) then you can just scoop what you need and add water.

There is no need to pay for Heat Stop at $100+ for 50lbs. Sand and Portland cement is cheap, and hydrated lime and fire clay are each $10/50lb bag. I mixed up half a 5gal bucket at a time and kept it covered between uses.

Blending your own 3-1-1-1 mix allows you to go a little lean on the Portland and rich on the lime if you feel like it.

[cobblerdave]

Re: Heat stop premixed mortar

G'day
If you only laying a few bricks in the evening use a plastic 20 litre bucket as a micro mixer. Measure you materials with a large plastic cup and the use a paint stirrer ( the big ones for drums of paint ) on your electric drill..... Instant micro mixer. Apart from being able to lay a few bricks at a time, clean up is easy and less damage and impact to fix up in you back yard as lime and Portland damage the grass and soil
Regards

[NCMan]

Re: Heat stop premixed mortar

I guess mixing a batch up in a bucket ahead of time would work for me. I know the key part is making sure the sand is bone dry and keeping it covered. I like that idea, plus the ability to adjust it if need be. Thanks.

[Gulf]

Re: Heat stop premixed mortar

I guess mixing a batch up in a bucket ahead of time would work for me. I know the key part is making sure the sand is bone dry and keeping it covered. I like that idea, plus the ability to adjust it if need be. Thanks.

You've gotten some great advice on the "3-1-1-1"..... "homebrew". I would like to add just this, from my own experience with laying just a few brick at a time as time would allow. I used a window screen to sieve and bust up small lumps on each and every mix. It will help make your small batches a lot easier .

[NCMan]

Re: Heat stop premixed mortar

You've gotten some great advice on the "3-1-1-1"..... "homebrew". I would like to add just this, from my own experience with laying just a few brick at a time as time would allow. I used a window screen to sieve and bust up small lumps on each and every mix. It will help make your small batches a lot easier .

Do you mean to break up the small lumps after it is all mixed together? I'm guessing that's what you meant. And thanks to all for the great advice. I'm taking it all in.

[Gulf]

Re: Heat stop premixed mortar

Do you mean to break up the small lumps after it is all mixed together? I'm guessing that's what you meant. And thanks to all for the great advice. I'm taking it all in.

Just to be clear, I'm talking about both steps in dry mixing. But, most importantly, just before you mix the dry homebrew with water.

After opening a bag of portland and placing it in five gallon buckets or sealing it up in plastic, it will still form soft lumps after a day or two. Humidity is the problem in the south. That may not be an issue in the desert southwest.

It helps to screen/sieve those soft lumps when making the homebrew. If you mix up a batch of dry homebrew which is to be used over several days the same holds true. Screening it back through a sieve before wetting will help with thoroughly mixing each small batch. Any lumps that aren't broken up easily through the screen should be discarded.

If you don't screen, it is more dificult to get a smooth mix if there are small lumps present. Any small lumps, which don't get mixed properly, (that make it in to your final mortar), can cause problems in brick placement. That "peanut butter" consistency, that you think you have, can be decieving.

[NCMan]

Re: Heat stop premixed mortar

Great tips and it all makes sense, now that you explained it all. Thanks for the advice. Now I just have to figure out which window to rip a screen out of. Maybe the wife won't notice one missing. Just kidding.

[NCMan]

Re: Heat stop premixed mortar

I have another question. I poured my hearth slab today. Have it all covered up for a few days. How soon should I think about adding on the next layer of Perlcrete? Should the slab be dried a bit? Either way, I'm going to keep the slab covered up awhile, just want to know if it's better to let the slab dry out a bit before adding the Perlcrete. Also, I plan to add about 4" of Perlcrete, then have the floor brick on top of that. I know it's not a great amount of insulation under the slab, but it should be fine, I guess(?)

[Gulf]

Re: Heat stop premixed mortar

It is good that you are leaving your hearth slab covered for a few days. 14 would be great. Your slab needs to stay moist for curing (strength) which I am sure that you understand. But, you don't have to let your slab "dry out" after that before adding your insulation layer...............If ......you install a waterproof membrane between you hearth slab and your insulation.

You could cover your hearth slab, after just a few hours of the pour, with a thick plastic. The next day you could install your insulation layer. In your case the "real wait "comes after the perlcrete .

[NCMan]

Re: Heat stop premixed mortar

I'll leave it covered for a week or two, for sure. Do you think that the 4" of Perlcrete under the hearth floor is fine? I know more is better, but elevation wise, 4" works. I can go higher if it's that critical. As of now, I plan to pour 4". And I'll be sure to also place another layer of poly in between the slab and the Perlcrete when the time comes.