I had a broken up molded up foam. I couldn't find an unmolested one, so I went to the hardware store, and bought this glue that was made especially for that shipping mold. It looked like Elmer's glue-(white milky stuff). I applied liberally on each facing sides. I just pushed it together, and laid it on the floor. When it dried, it was just as strong as the original.
That's if you can't find a good one.