My son is making mould & deckle papermaking frames for me using pinewood. The frames are continually immersed in water. Could you please suggest the best glue to use for this job?
As with most things there's no one best option. There are three good choices that aren't too difficult to obtain and should be absolutely reliable:
These are in no particular order. The epoxy does not need to be marine-grade.
As well as going with a waterproof glue for this sort of application it would be best to use corner joints that have some structural strength, so that you aren't only relying on the glue bond.
So in essence use anything but plain mitres. These are inherently not strong structural joints because two end-grain surfaces are being bonded together and this is the weakest of all glue situations. If going with mitres some further reinforcement should be considered mandatory.
Preferable joints would be one of the following:
- Mortise and tenon (wedged or drawbored ideally, pegged as a third option).
- Bridle joint, which can be pegged if desired.
- Halving joint AKA half-lap joint (can also be pegged).
- End-grain to long grain butt joint, which can be reinforced with a through-dowel or screw*.
Note these are in approximate order of preference.
*Stainless steel or brass/bronze in preference, although it appears plain steel fixings are used in the frames in use with many paparmakers as odd as that seems.