I was talking to a lady about table puzzles. She said she likes to shellac them on the back, once she's got a puzzle put together. She said she used to have trouble turning over a completed puzzle, but she has finally conquered that problem.
She now uses "Glad Press 'n Seal" brand of food wrap for that. She tears off a piece of this brand of kitchen wrap, and places it over the completed puzzle. She then runs her finger on the wrap around the edges of the puzzle, thus making it stick to the puzzle. She is then able to turn the whole puzzle over, so she can put the shellac on the back.
Once the shellac is dry, she can remove the plastic wrap and her job if finished. For those interested in this, no other brand of kitchen wrap will work, like brand I mentioned above.
By Terri from NV
Another way is to simple seal the front with wide packageing tape you get at the dollar tree!!
I also get poster board from the dollar tree and glue each piece, once I know it's where it is suppose to me. Then, when completed, I trim the paper from the puzzle and seal the front with shellac, tape, or puzzle sealer.