Refractory mortar vs castable?

[Dave M]

Is refractory mortar, like RefMix, the same as refractory castable?

Could RefMix be used to cast whole shapes like dome entrances or small domes?

Thanks,
dave

[Dave M]

This seems like a pretty straight fowrard one, no body knows the answer to this?

[dmun]

The short answer is no. Like regular mortar mix differs from concrete mix (it's sticky and has finer aggregates) castable refractory is different stuff from refractory mortar. Mortar might well crack when used that thickly.

[Dave M]

Originally Posted by dmun

The short answer is no. Like regular mortar mix differs from concrete mix (it's sticky and has finer aggregates) castable refractory is different stuff from refractory mortar. Mortar might well crack when used that thickly.

As I suspected, but I wan't sure if what was being called "mortar" in the case of RefMix was infact true mortar or cement used as mortar to bind the bricks.

Thanks for the reply.

[CanuckJim]

Dave,

I'm no expert on the exact composition of castable refractories, but I have used a fair bit of them. Castables contain refractory aggregate as well as refractory cement. The two types I've used are Kastite Lite (which is not meant for direct flame exposure) and Kastite (which is). The difference between them, as I understand it, is the percentages of of alumina and other materials. An equal cubic measure of Kastite Lite would be significantly lighter when cured than Kastite. There is also Super Kastite (which is even denser). I have cast vents out of Kastite and will be casting a lintel out of it next week, but I've never used Super Kastite.

Jim

[james]

RefMix is a mortar used to set precast pizza oven and fireplace pieces as well as fire bricks. It is very smooth, like a masons mortar. As others have noted, it is designed to be applied pretty thinly. The technical spec limits the thickness to about 2 1/2".
James

[Wlodek]

Just to add the castable side: the helpful man from Purimachos told me that I can use the castable (the one he suggested, not just any) to join elements of precast ovens.

Best wishes,
W.