Yes, you can easily use ArtResin epoxy resin over a puzzle. Cut a piece of MDF board to the exact dimensions of your puzzle and adhere your puzzle to the board with white glue. It's always best practice to pre-treat your puzzle with a sealant first, as the resin may soak into the paper and make it look darker, especially around the perimeter of each puzzle piece. Measure, mix and apply the ArtResin epoxy resin. Often puzzles require 2 coats because air is released from between the pieces in the puzzle which tends to create pitting in the first layer. A second layer will take care of any surface imperfections. Always remember to sand in between layers to encourage proper adhesion.