This was in reference to a deck repair – what glue to use to apply teak planking to a plywood substrate. It makes general comparisons between the glues
Epoxy is gap filling – so if there are gaps between the ply and the deck substructure the epoxy will have no problems.
With a deck done in this way you don’t need to use any permanent fastenings (screws or nails). You can use gyprock screws put in with a battery powered drill (one with a clutch) – and pull them out when the glue has set up. Plug the holes with epoxy and glass or dynel. I usually use glass when I do decks (not on small sailing dinghies though – too heavy)
Resorcinol is a very fine glue when you can make sure the fits between surfaces are very good and can get high clamping pressures. It is a dirty brown colour and tends to stain. All exterior/marine/aircraft ply is glued with resorcinol.
There are gap filling resorcinols around now, but they don’t seem to be commonly available. I would suspect that they are not as gap filling as epoxy and are still the same old dark colour.
Many of the criticisms of resorcinol – the tight fits and the high clamping pressure – are also limitations of the polyurethane and waterproof PVA glues. Epoxy is the only glue at the moment which is reliably gap filling.