Here are a couple of photos of the latest wood stove secondary burn modification. The first picture is the overhang that needed to be cut to make room for the secondary burn fresh air supply.
The second picture shows the new upside down "L" shaped fresh air supply. It will have three removable tubes with small holes in them. Its just sitting in there for the picture. Holes will be drilled in the upside down "L" shaped for the three fresh air tubes next.
Then the fresh air slots will be cut on the bottom of the stove on each side and the "L" will be welded to the stove.
My other wood stove, which is EPA Certified, does not have a control for the fresh air going in the upside down "L". I was thinking of adding some kind of control to adjust the fresh air, but will wait until after I fire it up to see how well it works first.