I use a piece of foam board from an arts & craft store - Michaels. It is basically a rigid foam sandwitched between two sheets of white plastic. It will be located near the picture frames because I think it is used as a mounting/backing material for picture frames. You could buy two and tape them together or buy one, cut it lengthwise and then tape them together. I bought a piece of it and it works very well even for laminants. The one I got is about 1/2 - 3/4" thick so you can push the pins in at angels if you need to. The cost is only a few bucks for each sheet.