For Christmas, we got one of our grandsons a puzzle.  When finished, I wanted to frame it for his room.  Thus the problem.   I did not want to use ModPodge because I was concerned it might bond with the glass.   It was very fragile to try to move and irregular shaped.  So how to mount it to a mat board, preferably by gluing.  Looking for ideas, I called Titebond's tech service and stumped them.   Finally decided on the following:

• Flip over onto the glass and do a positioning
• Apply glue to the back side.   Titebond original around the middle and a bead of Quick & Thick around the perimeter.  Hoping it would hold the pieces in place, not squeeze out, an dry clear if needed.
• Flip the mat board over the top, carefully aligning with the glass
• J-roller and apply some weight
• Let dry

 

I think we have success.   I need to put in the frame and secure with points, but thimk I got it.

Do you think crafters glue would have glued the puzzle to the mat board?  

Looks great Keith!

Great idea Kieth ! A gift that requires some input from your grandson and the final result is excellent. 
Paul

Fait accompli

 

Fait

Very nice!  Excellent way to fix the work in place.