If you build boards, you have probably encountered this issue - decks that twist along the length. The purpose of this thread is to share tips for preventing warping.
Veneer prep:
- many veneers are slightly warped or "cupped" - when arranging veneers in the layup, [EDIT 4/20/21:] cup them all in the direction of the concave (alternating the cup actually seems to increase chances of warping).
- incorporating more plies seems to make warping less likely (I've seen less warping on 8 or 9 ply boards made in a two-stage glue-up).
- store veneers in a temperature- and humidity-controlled environment.
Gluing:
- make sure the glue is distributed evenly on each veneer, especially if vacuum-forming the deck (there's nowhere for glue to squeeze out to).
- do the layup in multiple stages, especially if you find yourself finishing the board pressing towards the end of the glue's working time.
- let the glue cure for at least as long as the manufacturer's recommended cure time (or time until you can stress the glue joint) - the board is being glued up under stress (the wood doesn't naturally want to bend into a skateboard shape), so taking the board out of the press actually puts stress on the joints.
Post-cure:
- cut, drill, and sand the board as quickly as possible in a temperature- and humidity-controlled environment to prevent wood expansion and contraction, and then clearcoat the board as soon as possible. Store any unsealed boards in a bag or other humidity- and temperature-controlled environment.
Finished decks:
- don't leave boards out in heat (like a hot car or in direct sunlight), get boards wet, or leave the boards weighed down / stressed.
Please share your tips for helping other builders resolve board warping!