Build a High Efficiency Fireplace (90% Efficient!)

It's possible to build a high efficiency fireplace using cast clay for the firebox and sheet metal for the stovepipe.

066 efficient fireplace 1,2
[1] After making a cardboard template, Bob Christensen outlines the borders of the modified Russian fireplace. [2] Alex Sanchez prepares to halve the wooden mold at its midriff.