Question about layering proprietary castable and homebrew in one casting

[AndrewT]

What are your thoughts on this please.

I see from another post that to make a 34" dome with 3" thickness out of proprietary castable I would need to buy 10 x 25kg bags of the castable @ $55 / bag = NZ$550 (US$400). It is quite expensive in my country I think compared to the US.

I'm thinking perhaps I could just buy maybe 3 bags of castable and make a thin layer (maybe 3/4 inch thick), then build the rest of the 3 inches up using homebrew..

I have read and read (and read and searched) on these forums and I haven't seen that anyone has mentioned trying this before.

Does it seem feasible or can anyone think of some reason why this wouldn't work?

The castable that I can get here is called Shinagawa Shiricast 125. Does anyone know anything about that product please? I don't have a source of stainless needles so I would need to omit those.

[david s]

Most cast ovens are 2" in thickness. I don't know how the two different materials would work together, but I think you'd have to lay up the homebrew straight over the castable , say within an hour, to get a decent bond.

Check the density of the Shinagawa castable it should be around 2 kg/litre (2000kg/m3) you don't want an insulating castable on the inner surface.