Refractory Cement question

[ML38]

Hello,

I've come across some refractory cement KAST-O-LITE® 26. It looks to be for use as a castable cement but can anyone tell me if it is this something I can use to construct the dome or will the 1/8 " mortar joints be too thin or this type or refractory cement?
Thanks

[david s]

That stuff is a high temperature insulating castable. It's not a mortar. It contains high temperature aggregates that are not required for pizza temperatures and it also contains light weight aggregate that reduces its density, also something you don't want because that reduces its strength. I suggest you use what we call home brew 3:1:1:1 fine sand,Portland cement,hydrated lime, powdered clay. If you want to cast an oven use a dense castable not an insulating one.

[justing]

I have a question that is along the same lines and my garner the same response.
Years ago I worked as a laborer for a mason that is no longer around. We built a custom wood fired commercial pizza oven for a local restauranteur. Fast forward 10 years, I'm now GC on an otherwise unrelated restaurant project for that same restauranteur. He has asked if I could go over and patch a hole that has developed in the bed of the top oven (double decker). He does not, however want to stop firing the lower oven to do the repairs. Replacing the brick is not really an option due the heat that would be present and the fact that someone would have to basically crawl inside of the oven to do the work. He is OK with a bandaid fix of filling the hole with cement. Can I use the above mixture in a situation where it would cure at a relatively high temp?
Thank you

[david s]

You probably won't have too much success then. The method of patching repairs is as follows.
1.Dampen the area to be patched first. This has to be done several times because the material is so dry and porous. If the castable is trowelled in against surrounding dry material it won't adhere. The surface should be damp but not wet.
2. Make up a thin slurry of sieved castable, so all but really fine aggregate is removed. Paint the surface of the area to be filled with this mixture.
3. Mix some castable to peanut butter consistency and trowel the it into the area to be patched, forcing it in as hard as possible.
4. Keep the area damp with wet sand or hessian for 24 hrs.
5. Allow to dry slowly before firing then fire very slowly up to operating temperature.
Alternatively there are proprietary repair products use as directed.

[justing]

I greatly appreciate the input.

[Ocm6250]

That stuff is a high temperature insulating castable. It's not a mortar. It contains high temperature aggregates that are not required for pizza temperatures and it also contains light weight aggregate that reduces its density, also something you don't want because that reduces its strength. I suggest you use what we call home brew 3:1:1:1 fine sand,Portland cement,hydrated lime, powdered clay. If you want to cast an oven use a dense castable not an insulating one.

Hello, Regarding the home brew recipe. Are the quantities figured at weight or volume? Thanks!

[UtahBeehiver]

home brew ratios are by volume