For butt bonding pieces together to make them longer/wider or for laminating sheets to make them thicker what kind or adhesive is recommended?
Coastal Enterprises makes, and therefore recommends, a one part urethane adhesive, PB Bond-240, that is specifically designed for these purposes. PB Bond makes it very easy to perform both types of bonds. PB Bond is waterproof, solvent proof, plus it carves and sandblasts similar to the basic substrate. Check out the data sheet and also the application sheet.