Step 1: Building the wood gas stove.
Having the 1/2 gallon can upside down, mark the diameter of the 1/4 gallon (in my case was 10 cm) as centered as possible. I marked 12 mm all around. The next step is to draw yet another circle inside the one already made, in order to make a good set of tabs to seal the inner can inside the outer can. (See figure 1)
After you draw the three lines, cut at the inner line, sand the edges that are going to be quite sharp, and using a triangular file make "v's" like the ones shown. (See Figure 2). Additionally, drill 16 1/2" holes at 1 cm from the top (remember the inner can is inserted on the bottom of the big can, that is, upside down). That is all for the 1/2 gallon can.