I am asking for donations of empty coffee cans, sand, and glass jars (like jam jars, or small pickle jars) because I am building off-grid heat units for the people stuck living in tents this winter.
i'm making the wick out of felted carbon, so they last forever
Heating a room or a greenhouse can become expensive quickly. This sand and copper powered heater can heat for days using a vegetable shortening double or qua...
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