Missing Pieces
Perfalock puzzles are no longer being made, so it is not possible to go to the manufacturer for replacement pieces. There are however, still options.
Because the foam backing for Perfalock puzzles is unique, most replacement services and techniques will not be able to help. The solution is to get another puzzle of the same size and use the corresponding piece. If it is the same puzzle, the problem is solved. If not, an image can be taken from the puzzle illustrations on this site, printed and affixed to the piece. This will work for the 500 piece puzzles (poster and smaller size). The 1,000 piece puzzles present a different problem.
Not all of puzzles are cut the same. In some cases, the image was rotated 180° or reversed prior to cutting the pieces.
These two Wingmaster puzzles are an example of flipping the image on a vertical axis (right to left).
This means the puzzle pieces will not be directly interchangeable.
Even if the orientation of the image is correct, pieces may still not be interchangeable. Changes were made to the cutting die, or there was more than one of them. All of the cuts use one of two general layouts. That is, arrangement of pieces have the same basic shape, the same number and arrangement of tabs and slots. The differences between the two layouts are two edges out of the 1,935 reverse the tab and slot.
Within and between these layouts, many pieces are essentially the same shape and can be interchanged. Not all cuts, however, are the same. Some differ only in one edge, while others are in the dozens and some vary by hundreds. The variations range from slight (barely noticeable) to major (would not fit). Some variations occur at a single edge, so that while one piece may not be interchangeable, pairs may be.
Even if pieces match, variations in how the cut aligns with the image, or variations in colouring may make substitution difficult.
Bear's Den
Top left corner
Most of the cut variations I've run across for a given image are associated with a change in packaging although there enough exceptions to make it pretty bad as a rule. The most I've seen is 5 variations in The Original Six, among my 7 made copies, with 2 still to go. Other differences have been found within Bear's Den, Country Cooking, Fairy Tales, Fire Call, Graceland, New York City, New York Skyline, Old Fashioned Kitchen, Summer in Bloom, Wingmaster, Winter Blessings and Winter Lace.
One of the cut variations was used across 30 different puzzles, another was only used once. My original taxonomy had 5 variations based on 10 pieces in the upper left. But verifying each specific puzzle at a detailed level drove it up to 12 and counting. It was getting much too complicated to explain on this site and frankly hard to explain to my wife why I'd want to. So the results so far will remain buried on my hard drive.