Fire clay Mortar Vs Refractor Mortar FB.... HeatStop... Earthcore Finding Building Materials Discuss Fire clay Mortar Vs Refractor Mortar FB.... HeatStop... Earthcore in the Pizza Oven Design and Installation forums; I am wondering about .....What motar can i use for my fire brick pizza oven? What is the differance between ...

[100million]

I am wondering about .....What motar can i use for my fire brick pizza oven?

What is the differance between Refractory mortar (premix) like FB or Heat Stop Drymix and the lower cost modified portland cement fire clay sand and lime mix?

Is the Premix for use with fire brick ovens the same the modified?

Are they both the same strength when used between the fire brick?

Has anyone heard of Earthcore Mortar used with ISOKern fireplaces modular systems.. Earthcore Industries, Inc. - Mortar

[Les]

The Ref Mix and Heat Stop are top of the line, easy to work with and is diamond hard when dried. Many have used the "roll your own" with great results. I have used all three. I think it comes down to your wallet. I have never heard of the Earthcore product, but if it's for refractory builds, it will most likely work (unless it is made up of nasty stuff).

Les...

[kebwi]

As with many others here, I used the "homebrew": silica sand, fireclay, portland, and lime (3:2:1:1). Working great for me, although I would recommend a smaller sand grain size than the #30 I used. Finer sand would produce a mortar that would spread more evenly in the tighter joints.

[Raffy]

Hi All,

I've just used a fireclay mortar with the generic name of sk32 mortar. I'm kinda worried that this mortar will not be able to stand up to the task when it comes to the dome and arch design of a pompeii oven. I just applied it to a few bricks and it still hasn't set after 3 hours. It doesn't set like cement and has a clay consistency. I called the people who sold me this bag and they said it should have set already in a few minutes. I mixed up a batch and bonded two bricks together and I'll test out its strength after it has cured properly but i don't want my current work to be for nothing if a week from now I discover that this SK32 Mortar is crap.

I'm a total stranger to mortar and its characteristics so is this normal for a fireclay mortar. Should mortar only be used as a thinset? Sorry if I sound desperate but I'm freaking out cause I've never really worked with mortar and I'm used to the immediate hardening of cement once it has set.

Raffy

[Raffy]

Is fireclay the same as fireclay mortar? My confusion stems from the fact that the people I bought the fireclay from said that the fireclay mortar is all I need. They instructed just to add water and apply. Should I use this SK 32 Mortar by itself or combine it with lime cement and sand in the home brew high heat mortar.

[dmun]

Is fireclay the same as fireclay mortar?

No. Fireclay is a powdered clay with heat resistant qualities. You can build your dome with a fireclay/sand mixture, as Frances did, but it's not waterproof.

Our homebrew mortar uses fireclay as one ingredient. I don't know what "fireclay mortar" is, in the context you are using the term.

I googled SK 32 mortar, and found no information, except for a couple of Indian and Chinese exporters listing it among the products they sell.

Sorry I can't be of more help.

[Raffy]

Hi Dmun,

I guess a better way to rephrase the question is can fireclay by itself be made into a mortar if not then I guess its safe to assume that this SK32 Fireclay Mortar that these exporters are selling already contains additives that will help bond bricks and other refractories together. I asked around and I found out that SK refers to heat capacity. So, as the SK number rises SK32, SK34, SK36... so does the max temp. My firebrick is graded SK32.

Another question springs to mind, could it be that SK32 Fireclay Mortar is in fact an airset mortar which only strengthens when it is fired? If thats the case I'm better off with the homebrew since I can't use airset in an outdoor setting. Boy, am I confused.

Need to research this fireclay thing more thoroughly. Sigh...

Raffy

[james]

In layman's terms, mortar requires a binder and aggregate/additives. The binder causes the chemical reaction that transforms the mix of binder and aggregate into a material that hardens and cure.

With the home-brew mortar, Portland cement is the binder, and sand, fire clay and lime are the aggregates and additives. Fire clay gives the mix a little bit of resistance to thermal cycling, while the lime makes it sticky and workable. But without Portland cement, it will not set and become hard and waterproof.

With a refractory mortar (such as FB Mortar), the binder is calcium aluminate and the aggregate is a composition of refractory (heat and thermal cycling resistant) materials. There are also additives the make it sticky and that help it harden a little faster.

I cannot tell from you description what you product is -- though I can confirm that the SK terminology does have to do with the composition of materials (it also applies to firebricks).

I hope this helps a little.
James

[berryst]

I used lime, clay, sand, and portland cement. My major concern was spalling. To date, after a couple of years use no spalling has occured.
I would use it again.
berryst

[Raffy]

Originally Posted by james

In layman's terms, mortar requires a binder and aggregate/additives. The binder causes the chemical reaction that transforms the mix of binder and aggregate into a material that hardens and cure.

This helps a lot, James. I'm beginning to suspect that this mortar is "activated" by heat. There doesnt seem to be any binder of sorts cause it doesnt harden. In fact, I went out to check it this morning and it seems to have softened. Maybe the moisture of the early morning air softened it.

I'm not sure this company knows its terminology but SK32 mortar doesnt really bind like a mortar or harden at all. Maybe SK32 Mortar is simply fireclay... but that doesn't explain why they would say just add water. Sorry just thinking out loud.

Anyway, thanks for the help, James. Based on your reply, I wont be using this product on its own. If in fact it is just ordinary fireclay and not a SK32 Mortar as they have labeled it then I'll use it for the homebrew.