Ran across an article last night in the new On30 Annual suggesting a foam adhesive called PL300 the author used for his foam base. I'm not familiar with the product but it could probably be found at the BORG (Big Orange Retail Giant) Store. If not, There's Liquid Nails and other construction adhesives available in both squeeze and caulking tube. Most all of these are going to give a permanent bond so don't even think about changing anything after the glue cures!