This is a wooden hammerform,of birch plywood, made in the shape I want the finished part. The profile is cut on both sides with a router, so I can form a left, and a right with the same form. The notch in the blank is made where the metal would fold when making a compound curve, that is too much to shrink. Make sure you have extra material beyond the bend to trim a straight edge later.
The back side of the blank is backed up with another piece of wood cut small enough to allow room for the hammer/ caulk to make the bends in the blank.
Bending the first side with a plastic mallet. Move back and forth a lot, and don't hit too hard, many light hits are better.
Clamp the first side in place after bending.
the caulk is used to bend the blank in the compound curve area that is hard to reach with the mallet. Don't hit it hard, or the metal will stretch, instead of shrinking. The caulk is made of very soft steel, aluminum, copper, plastic, or even hardwood. It can be shaped to form curves if necessary.
Desoto Firewall Recess(Cont.)