Things You'll Need
Instructions
Assemble the puzzle fully on a piece of cardboard or wood. This will allow it to be moved easily if necessary.
Apply a thin layer of puzzle glue to the top of the puzzle using a brush or sponge. If you don't have puzzle glue, you can use regular white glue. Allow the glue to dry completely.
Apply three more layers of glue, letting the puzzle dry completely between applications.
Turn the puzzle over and apply a thin layer of glue to the back side. Allow it to dry completely.
Place something heavy, such as books, on the puzzle to flatten it if it's warped or bent at all.