Teacher of Arcane wrote:Hi All,
I would like to build a temporary rocket mass heater this winter to provide heat while my wife and I work on the interior of a house under construction. My question is what materials would make the best heat 'batteries' for this stove.....sand, gravel, ...... 
Don
Sand is bad, gravel is better...
cob, brick (if it can be kept in contact with the metal) or stone (same as brick) are even better. The big thing is contact through out the mass... but air space if there is any
should not be trapped (like sand) or it insulates. For temporary use, maybe whatever is on hand is fine. There is no good experimental data for a lot of these things. If you are only working during the day... maybe no mass or a pocket rocket will do fine too.
