Well, I've been planning the rocket mass heater for my home for a while now. I have spent the last few months reading, planning, getting materials, in anticipation of this project. Today, I started physically working on it for the first time. I'm excited, so I thought I'd start this thread as a place holder, and I'll get pictures of the steps up here as I go.
Today I built a two part mold for the combustion unit, as I'm calling it, which consists of the feed tube, burn tunnel, and base for the heat riser. I will be molding those components out of a clay slip with mixed perlite to make an insulative castable refractory. I might line the impact areas around the feed tube with some fire bricks so when I'm banging logs around in there I don't chip away at the refractory.
The mold is made of 3/16 masonite I had laying around, and consists of a piece the shape of the combustion tunnel. That is, a "U" shape, with short horns. Then the outside mold, which is just a box that holds the U with 4" clearance all the way around. I just cut all the pieces out with my hand saw and glued 'em together with hot glue. We'll see how that works. I'll get some pictures up on pour day. Maybe tomorrow!?
I may do the heat riser the same way, I'll see how this goes. Anyway, I'm kinda jumping the gun, but I'm excited!