I'll be quite brief from here as there will not be much theory to what I do. To begin with I put a piece of paper under the finished (almost) puzzle and traced the outline of each of the missing pieces and then used a hobby knife to cut them out.
When looking into my stock of hobby materials I found this flat sheet of hardwood that should provide a solid core for each piece.
To get the basic pieces thick enough I cut out two equally sized pieces and glued them together with regular carpenter glue, applying some pressure to the bond using a vice. I realised I should have glued the second layer at a 90 degree angle to the first one to get an even better foundation that would be harder to break, but it should make little difference as the pieces will be treated quite carefully anyway (I'm sure that I will get a chance to improve on all this when building future puzzles).
Next I glued the stencils onto the piece of wood as well to provide a solid reference when cutting out the individual pieces. To compensate for the mistake I made above when adding the sheets together I attached the stencils at a 45 degree angle so that the wood grain is never perpedicular to any of the sides making it easier to accidentally break a hook or a corner off when polishing.
Using a vice and figure saw I extracted the rough shape of each piece. Then using my Dremel and a grinding bit I further defined the shapes. Using even smaller polishing bits with the Dremel and small files I went on to make each side to fit into their neighbour pieces.
With additional polishing and repeated test-fitting into the complete puzzle I removed as much pressure on neighbouring pieces as possible before reaching a good enough fit. This particular puzzle have a small amount of play in-between the pieces that also made things a little easier. At this point the new pieces was also somewhat thicker than the other ones so I used a flat sheet of sanding paper to make them a bit thinner. I also sanded away the paper stencils that was glued onto the pieces as I won't need them for anything anymore.
That's about it for manual labor. Next step will be to reproduce the images for each piece in Photoshop. This should be the most fun part!Continue to chapter 3. Image reproduction