Adhesives
Properties of adhesives that you must consider are hardness, gap filling properties, and moisture reistance.
Aliphatic resin glue - Commonly refered to simply as white or yellow glue. Yellow glue is a somewhat more user friendly version of white glue. Because of this, I don’t use white glue. Yellow glue is the primary glue of many woodworking shops. A properly prepared glue joint is stronger than the wood itself. Properly prepared means that there should be only about 0.001” gap between the pieces of wood. More than this will seriously weaken the joint strength (as the water evaporates, the glue shrinks and is stressed from having to span too large of void.) This problem can be alleviated somewhat by “priming” the joints with glue, allowing a few minutes dry time, and then reapplying more glue prior to clamping. Speaking of clamps. they should be used, so that the glued joint or seam can be pushed closed as the water evaporates.
In short, aliphatic resin glues are very effective when used propery, but the joint will be weak if there is excessive gap or if clamps are not used. Remember also that glue smears, while drying almost invisibly, will repel the finish and show up as ugly spltches when finish is applied.
Polyurethane glue - This is useful for custom vacuum press venneering, as it has a long working time, and glue that has telegraphed thru the veneer has little effect on the finish. It is waterproof, and makes an extremely strong joint WHEN USED PROPERLY. If clamps or other pressure is not used, and if there are significant gaps, the glue will foam within the joint as it cures, and you will have minimum strength. Foaming outside the joint is of no concern.
Epoxy (fibrglass resin) - There are many formulations of epoxy and you want to be careful about the selection. Essentially, though, epoxy is a superior adhesive for many applications. It is waterproof, has excellant gap filling ability, and, depending on the formulation, can offer great stregth while still maintaing some flexibility.