Permsteading.com

Made four test pucks today.
1. All clay.
2. One part clay one part ash.
3. One part clay one part sawdust.
4. two parts clay one part ash one part sawdust.
The clay was a clay slip about the same as pudding.
Now the hardest part waiting for them to dry.
I will keep this updated as I get results.
I should add that this mix will be used to make a burn tunnel like matt walker did for his house. I also plan on adding fiberglass like he did in his cobposite. I hope he doesn't mind me stealing his ideas.

I don't mind at all. I will be curious to see what you find out. I've been thinking about the way I built my burn tunnel lately. In my new outdoor stove and in my neighbor's stove we used bricks in the burn areas, and it's amazing how much they affect the performance of the stove. Brick in the feed tube and burn tunnel leads to way more coal and ash build up, slower start up, and reduced draw and increased chance of smoke back, in my experience. That said, there's times when it's easy to throw 'em together and they work fine, but an insulated burn chamber really makes these things roar.

Keep us posted, I've got a few more stoves in my future and am still refining my mix, I'd love to learn from your experience.

My plans are to make a plug out of wood to form the burn tunnel with a trip wire in the top of the tunnel. Then make my mix thick and put it on the plug like cob and maybe wrap it with fiberglass tape in the high stress areas. This is after I find the right mix.

A link to the same topic on donkeys site. http://donkey32.proboards.com/index.cgi ... 504&page=1

That sounds like a plan. My experience with the fiberglass tape is that it creates a fault line where there is no cohesion, so I'd recommend using a chopped fiber instead. I used scissors and matte glass and cut it into about 1" fibers. Mix it well and it's really strong. One caveat though, don't put it where you will come into contact in regular cleaning and such. It is itchy, not terrible, but you don't wanna drag your inner forearm across it every time you clean it. Trust me on that one.

LOL from body work and boat repairs not counting carpentry I know all about the itchiness. I planed on chopped fibers mixed in and maybe wrapping some on top of the feed tube for strength.