I've been having the worst time finding a glue that is available for purchase.
Typically for Filon you use Stabond E-183 which is a foam safe glue that sells for about $300/gallon. It's solvent based and EXTREMELY flammable during application. The high VOC contents makes it difficult to get in some states.
RecPro recommends 3M 1357 which is around $155/gallon. It's also solvent based but not as flammable as E-183. I've had my 3M 1357 cancelled by some 6 different vendors now.
3M 5200 could be used but it comes in either tubes for use in a caulking gun; however, a tube is equal to roughly a 1/8" bead that's up to 152". As such a 4x8' panel would require a very large number of tubes.
I've decided to try out Titebond Advanced Polymer adhesive which comes in a 3.5 gallon pail for about $200. It's quite toxic and requires a hazmat mask and gloves when applying but so are E-183 and 1357. It's different than the Titebond FRP adhesive in that it cures from moisture and not from drying.
I'll let y'all know how it goes with this product after I try it.
If there are any other suggestions on products to use I'd love to hear them.