14-09-2017, 11:08 AM
(13-09-2017, 10:03 PM)Mark Atkinson Wrote: I think that aviation and marine grade Plywoods are a wonderful flexible material with excellent strength characteristics. I do not believe that they are subject to degradation by wetting or heating, so long as these treatments are done within acceptable parameters. I used marine grade birch ply on the car which was manufactured in Finland. I do not have any concerns about the adhesive after the wetting, it is manufactured to a set of standards which allow for just this sort of treatment. I doubt, but may be wrong, that the resin based adhesive in these plywoods flow or in any way move during the processes of heating and wetting, as the ply would also relax allowing for the materials integrity to be reduced because it would start to delaminate.
Interestingly, back in the 1930s Airspeed made aircraft using a bent ply wing spar mountings, which had a 90 degree bend, I have never read of any structural issues resulting with those widely used aircraft types
Regards, Mark.
Thanks, Mark, very interesting. I hadn't heard of marine grade birch ply.
My local boat building timber yard stocks Baltic birch ply and tropical marine ply. I much prefer birch ply so will check whether it is marine grade.
Thanks again, John