High Heat Mortar Primer

[Chaos]

Re: High Heat Mortar Primer

Just had a quick question...

...I have the Casa2G110 kit and I'm getting ready to start assembly, but I can't seem to find directions on using the high-temp mortar (i.e. how do you mix the dry mix to create the mortar, etc). Is it just like mixing cement (i.e. 3/4 of a gallon pf water per bag), or is it something else?

If this is discussed elsewhere in the forum, a simple redirection/link would be appreciated.

Thanks!

[sutto]

Re: High Heat Mortar Primer

Has anyone tried a mortar using Calcium Almuninate Cement with Fireclay?. I read about Francis using Sand and clay, though i don't know what ratio she used. I have made a trial batch using AC Cement and FC at a ratio of 1:3 and it seemed quite workable and was very sticky, though how it will handle oven temperatures i don't know.

Sutto

[GianniFocaccia]

Re: High Heat Mortar Primer

Haven't heard of or used CA mortar but reading up on it, sounds like it has favorable properties including water-resistant and it sets up rather quickly. Refractoriness good to 1400C. Maybe you could bond some bricks together and heat them in the barbie for a test.

[mikesuttie]

Re: High Heat Mortar Primer

Hey guys!
I'm currently on my dome course and using the homebrew cement, lime, sand,fireclay mix but having issues and the mortar doesn't seem to be bonding to the bricks properly! I built the outer arch from normal clay engineering bricks and 2 days after laying it the brick just came off. Is there any way to ensure the mortar binds properly with the bricks?

Also as it dries it cracks like a biiaatch!

[david s]

Re: High Heat Mortar Primer

sutto,
All clays will shrink on drying so without the addition of sand you risk a reduction of bond strength. The sand also acts as an extenders making the mix way cheaper. Try 4:1:1 sand, CA cement,fire clay. Also be careful that the fireclay is real fireclay, stuff sold by Cement Australia as "Bricklayers Clay, Fireclay" is actually not fire clay and does not handle heat.I have called them to complain about this, but they won't change the packaging for just one complaint.

[sutto]

Re: High Heat Mortar Primer

Mike,

Something's not right for sure, i wonder what it is?

It sounds like you've just started with you brickwork. Have you for sure got the right ingredients in the right proportions? Those engineering bricks are probably not very porous and will benefit from being soaked for while. Even more so if the weathers warmish.

David

I'm going to stick with Portland, Lime, FC, Sand. 1:1:1:4. Better the devil you know.

Sutto

[mikesuttie]

Re: High Heat Mortar Primer

Cheeers for the reply!

At the moment i'm laying everything with no probs but a day or so after the mortar has small cracks on every join. I'll just have to fill them. I'm using 1:1:1:3 (portland cement, hydrated lime, Fire clay, standard builders sand) so maybe I'll change it to 1:1:1:4 ?

Cheers! Happy building/pizza making to all

[mikesuttie]

Re: High Heat Mortar Primer

I think I've worked out what may be the problem, I'm making my joinings way too large. having looked at other peoples domes I can see the bricks are far closer together and I'm evidently using far too much mortar. I'm on my 3rd course I think I'll have to live with the mistakes I already made and just correct them. Lesson learnt!

[Lars]

Re: High Heat Mortar Primer

Mike,
I would cut down the lime and use the extremely fine sand ( for smaller joints) Here in the US, it is widely available and only costs a little more than 'all purpose' sand.

I am sure the 'recipe' I used is on here somewhere. 3:2:11/2) (sand, clay, portland, lime)

Just made pizza last night... and we have been using it regularly for about a year. ( regularly = about once a week)

Lars.

[mikesuttie]

Re: High Heat Mortar Primer

Sounds awesome! Looked at your build and it has really confirmed what I've been doing wrong. Your dome bricks are all nice and tightly pack together whereas mine are miles apart with a load of mortar in them think I may have to rethink things a little. Question is do I knock it down and start over or just correct it and hope for the best!! Dilemma!

[azpizzanut]

Re: High Heat Mortar Primer

Hi All,

Look for silica sand at the following sources:

Welding supply, it's used for sand blasting operations.
Swimming pool supply store. It is used in sand type water filters
Brick yards
Masonry supply stores
Foundry supply, it's used for making sand molds.
Painter's supply, it's used to mix textured paint.
Aquarium supply.

Cheers,

[jacktheknife]

Re: High Heat Mortar Primer

Gentlemen,

I read all the former posts on this thread but never heard
'Castable Refractory Cement' mentioned.
I used it when I built my propane forge and 2,000 degrees is nothing to the stuff. 1600 degrees is normal temperature while hammering metal.
Would Castable refractory Cement be of any advantage used on an oven?
Bricks are laid not with concrete but with mortar. I don't know why but then I am just a former roofer. Wouldn't cement be better?


Thank you...


Jack the Knife

[Tscarborough]

Re: High Heat Mortar Primer

Castable refractory is good if you are casting a shape, but not so good for mortaring together bricks. Use refractory mortar for that, and it is cheaper than CR anyway.

[jacktheknife]

Re: High Heat Mortar Primer

Tscarborough,

Thank you.
I was a music major at U.T. Austin Texas in the early 70's.

J. Winters von Knife

[Tscarborough]

Re: High Heat Mortar Primer

I was a High Schooler from Houston who spent my summers on the Southwestern campus lying by the river and on the Guadeloupe in the early '70s