Sheeting foam cores
I use 3M transfer tape. Cover the entire surface with it, peel that backing and put on the sheeting. 3M 77 spray works well, just make sure you wear a good mask. That stuff is really bad for you. Very high cancer causing. For putting sheets together, I get cheap electrical tape at the outlet store, tape 2 sheets together on the seam, bend it back and put thick CA in the joint, then wipe the other side with a paper towel. Sand lightly as the glue is drying and the dust will fill the rest of any crack. Take the tape off and sand that side lightly and the crack there will be filled as well. You get nice smooth sheeting that way. Be carefull not to sand too much thinning the sheeting too much.