@ Max, using concrete in my oven conversion. ..

[ronyon]

So I just stripped a wall mount style electric oven, readying it for conversion to rocket power.
This thing consists of three nesting cubes of steel.
I removed the insulation and intend to replace it with thermal mass.
Since it would not be directly exposed to the heat of the exhaust gasses would concrete be a durable choice for the mass?
I plan on mounting this oven over a "barrel" with a flue in between the two, Matt Walker style.
Pizza and bread are the aim, any feed back appreciated.

[satamax]

Hi Ronyon.

Well, i have hard time picturing it.

Could you make a drawing?

[byronc]

Sounds like you want to encase the metal box oven with thermal mass? Proper pizza oven temps. are generally bad news for concrete.

For high working temperature thermal mass, I'd go with something like "thermal cob" (approx 30% clay to 70% masons sand). Or for even denser thermal mass, you could use dense fire brick and or pieces of same, or clean rock (same rock as for concrete)  but mix it with thermal cob.

[Daryl]

Ok, this is not the type of stove you are looking to build. BUT check out the materials. I came upon this awhile back. Maybe this will help, maybe not.

The Fontana Forni 'Gusto' Outdoor Oven
www.9ghealthfoods.com/wp-content/uploads/2014/04/oven-inside.jpg
www.fontanaforniusa.com/wp-content/uploads/2014/02/dualchamber.jpg

www.youtube.com/watch?v=iNIV_YQidis

I could have sworn I have seen another outdoor metal cooking stove with plain firebrick as an interior liner but I can't find any examples now.