Making replacement pieces (Fix delaminated and broken pieces first)
Have plywood pieces in various thicknesses ready with watercolor paper attached. See Par. II.C.
Using caliper, determine thickness of puzzle piece. Note that thickness may vary throughout the puzzle, so measure close to missing piece.
Choose similar thickness wood for repair piece (w/c paper attached). A little thicker is better than too thin. The back of the finished piece will be sanded flush with the puzzle.
Remove pieces of puzzle around piece missing (make sure the section contains a corner or at least a straight side), and place section on prepared replacement plywood, lining up straight edge(s) if possible.
Use carpenters square to hold pieces in place.
Hold down with fingers. If necessary, use rubber cement to hold adjacent pieces together. Avoid getting rubber cement on the puzzle picture paper.
Trace missing piece carefully with Architects pencil and .05 lead. Be sure to remove rubber cement from surrounding pieces using finger or rubber cement eraser.
Using scroll saw and magnifier, carefully scroll replacement piece just outside the pencil line. Adjust your cutting to the fit of the rest of the puzzle; more outside the line for tight puzzles, more touching line for loose puzzles. For tight curls, cut into line. For very loose puzzles (Kingsbridge, etc.), cut on the line or even on the inside of line.
Check for fit, use needle files to smooth edges and release tight fit.
Sand back of replacement piece to level of surrounding pieces on self-stick sandpaper attached to block of wood. Sand in stages checking fit periodically.
If there is a large area comprising several missing pieces, cut one large replacement piece. Color before cutting individual pieces. To cut into individual pieces, turn large replacement piece upside down and trace other pieces from the puzzle in order to maintain the style of the puzzle. When cutting upside down, reverse blade so the saw teeth will not rip the paper.
Multiple replacement pieces can be cut from the same piece of papered plywood until it falls apart or becomes too full of holes to use.