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.
But it doesn’t fill gaps like epoxy. This is a 30 year old hartley powerboat. It has been stored in a shed for decades.
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.
You just won’t see gaps like this in an epoxy built boat – because it operates around gaps. The border of every component is bonded to the hull skin vastly increasing the strength of the structure.
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.
During the 60s and 70s those of us building and using plywood racing dinghies had an endless cycle of maintenance of leaky boats. That all changed with epoxy. NO MORE LEAKS and thus the need for much less major maintenance.
For an idea of how much Epoxy changed things in plywood racing dinghy building please read this article –
