Rocket mass heater without cob?

Can you build one without cob, like with concrete or something else if you don’t have access to clay?

Concrete would be a drag if you ever wanted to change or demolish the mass. Cob doesn't need all that much clay in it...10-20% will do the trick in many cases and that could be a bag or two of stoneware clay from the pottery supply. Manures make great binders if clay is in short supply, and once dry it won't smell at all (plus you can coat it with plaster or limewash). What sort of soil do you have on site?

You could always use a stratification chamber instead of a solid mass.

Mine is going to be!

This is the one I'm going to build.



Matt sells complete plans  too - Tiny Cook Stove plans