BustedHAMmer

Thank you, Frosty. The short answer, because we can! Haha. Yes, more of a proof of concept to test the viability of a concrete shell, or for an increased R value castable, water set refractory like Kastolite. I was wondering about the dragons breath around the outside. I have a stainless serving tub that's ~9"W x 6"T x 12"L I am planning to make with an internal dimension of 6"W x 4"T x 7" L (168 cu in). I plan to use 2 inches of 2600 8# ceramic blanket, rigidized and covered in~ 1/2" of Kastolite 30. This is all based on other posts in the Forge 101. The tub would have the ends cut for the openings, and a floor made to cover the " top opening" of the tub (which becomes the bottom) with the floor fixed to the lip of the tub and secured with a strong base and hearth in front and behind the forge. I currently have a coal forge I've been playing with to get started, enjoy it, and have back burned the gas forge for now (pun intended?), but will build this once I have more funds to work with. I estimated it would cost about $200 for my BOM with extra material leftover for future projects. The Aircrete was just a recent musing and wondered if anyone here played with the concept for a forge. I did not know that water set castable refractories did not have a binding agent. I know they are not cement or mortar, but I thought there was still something that would stabilize the material until it was fired.

I'm glad I found this post. There was a recent post on YouTube by NightHawkInLight on making Aircrete at home with readily available kitchen items, and my first thought was trying it with refractory material. After reading this post, it sounds like some have already considered and possibly tested it. For a preliminary test, I thought it might be useful to first make regular Portland cement aircrete as a shell for a forge, and then layering ceramic wool insulation, binder, and high temperature castable refractory as a final layer. Thoughts? I haven't made a gas forge yet, so I'm going off suggestions I've seen here in other posts, and other resources. My preliminary reading makes me think that adding the Xanthan Gum as a foaming agent to a castable refractory may have negative effects. The Aircrete shell would give a stiff, temperature resistant insulation that wouldn't hold up to direct flame, but with the 1-2 inches of ceramic insulation acting as the primary thermal insulation, the Portland cement wouldn't experience the degrading high temps.