High Temperature Mortar Materials from Mutual Materials

Mutual Materials sold me Type S mortar and fireclay instead of the items I asked for. They said the Type S mortar had the other three items already blended. Are they correct?


HECK NO! That is incorrect!

I made a batch of High-temp mortar this weekend and got all the materials needed at Mutual Materials / Bellingham location (see pic below).

Type S Mortar is great for the edge brick around the hearth slab… but NOT as a high-temp mortar.

We’ve never received a complaint about this inexpensive and easy to make high-temperature mortar that is used the world over. But you have to make it correctly… so don’t deviate from the High-Temp Mortar recipe.

Plz let me know the branch location. I’ll send them a set of our Installation Instructions.


2 posts were split to a new topic: Low, Medium, or High FIre Clay?

Thank you! And another question, should I add to mix by your recepy calcium aluminate or alumina oxide ?

Don’t add anything else.

Just the Silica Sand, Fireclay, Lime & Portland Cement.

This is a tried n’ true recipe (used the WORLD over). We didn’t invent it, but hundreds of thousands of pizza ovens are built with this simple recipe.

We have had ZERO complaints about this high-temp mortar recipe… and it is a LOT more forgiving than factory made refractory mortar (that costs a lot more).

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Second that.

There are a few items on the materials list you can adjust to fit your local conditions or supply availability.

The high temp mortar recipe is not one of them.

There is a reason it is called a “recipe.” This is just like baking: you can deviate from a cake recipe, as long as you don’t expect good results.

The high temp mortar recipe is a particular chemical mix that involves a reaction among the materials, and results in a new composite that stands up to the high heat of your refractory vessel.

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I know this is now an old post, but just wanted to add that Type S means “standard” or “stucco”—or at least it’s an easy way to remember its purpose.

You can use it for non-refractory purposes, and it’s an excellent mortar for your oven’s mortar shell.

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Thanks a lot for your time and patience!


And a question again, how important a hydrated lime type?, should I am looking for a specific one, N or S? Thanks

It is important to use hydrated lime. Quicklime or garden lime will push things so you can’t work the mortar. If you look at the photo upthread, you’ll see it is clearly marked “Type S”. And of course, that means something different for hydrated lime: it is special because it has to have a certain hydration content.

You can read all about construction lime at this link. But do it just to satisfy your curiosity. Use the materials that BrickWood specifies. I’m sure once you read about how lime is produced you’ll see why it’s called a “recipe.”

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What is the amount I should buy for the Brickwood Box? Does anyone know about it? The Materials list has 110 LBS, and the Material blend has the ratio, not amounts.

I realize the BrickWood Box Installation Manual is way too long (and I will have an abbreviated version some day), but for now, jump to Page 44 on the BrickWood Box Installation Manual.

The Materials List for the High Temp mortar is on that page.

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How silly of me. I actually thought these were the sizes of the bags and no the quantities I needed.

I did read through the end already, but I keep going back and forth.

Thank you

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@BrickWood will recall that when I was first considering my project I read and re-read the manuals for three different designs, and asked a lot of questions before I had it all straight in my mind.

It may help to recognize that the only circumstance under which you’d have to line up all these groups of materials in advance is if you have a specific, tight deadline for completing your project. In that case you’d want everything purchased and staged before you start.

Otherwise, it helps to break it down and line up the materials for each phase. And just from my own experience, it will all make much more sense when you are actually building.

I did enjoy all the research, and I hope you are as well. In the end, building this project is intended to be enjoyable!

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A post was split to a new topic: Firebrick and castable refractory for the BrickWood Box

A post was split to a new topic: Why can’t I use high-temperature mortar sold in a bucket?