When I glue on top of my jigsaw puzzle, will it stick to the cardboard behind it?

normaneu16: When I glue on top of my jigsaw puzzle, will it stick to the cardboard behind it?
I heard that I must put my jigsaw puzzle on a cardboard, then I glue on top of the puzzle. If I only glue on top of the puzzle, will it stick to the cardboard? What is the purpose of the cardboard? Is it supposed to be sticked to the puzzle or just to hold the puzzle together?

Answers and Views:

Answer by aoifeb2000
Use a thin layer of Mod Podge (available at any craft store)…A thin layer (or two) won’t stick to the surface it’s on…

Answer by davionmw
once you finish the puzzle, slide a poster board under it, flip it over, make sure the puzzle is still together, remove poster board, spread glue all over it and put it back on the puzzle and let it dry, i do this for wall pictures