Bending Plywood

[Erich]

Plywood has the grain running in two directions. Birch ply was the choice, I have learned, and still is. If it is 3 ply the outer two are in a single direction and the center one is 90 degrees to that. Experimental aircraft parts suppliers usually have birch. It is expensive. One trick I've used in building small boats when a compound curve is necessary, is to make light cuts on the back with a table saw. With steaming and lots of water, you can form the plywood in compound curves. The cuts on the back are later filled. Another method is cold moulding. Many wooden sailing dinghies were built this way. Basically, this means buying relatively thin veneers and glueing them over a mould. After WW2, the glue used was Resorcinal, though I don't know what would have used in period.

Erich in Seattle