I once had to join two pieces of foam in a hard to reach location. I used a water-based contact cement. I painted each with two coats - the first fills and seals and the second holds things together. They were only slightly tacky when ready to assemble. I put wax paper on the in-place piece, fitted the other piece on top, then slid the wax paper out an inch at a time. I was worried about the pressure distorting the foam, but this (non-minicell) was firm enough.

If you don't want to try that, the Goop products might work, not all of them are as grabby as Weldwood or 3M.