I have noticed most builders put the outside hull fibreglass onto the plywood without first sealing the plywood with epoxy. Is this the recommended way of doing it. My thoughts on this would be to first seal the plywood with epoxy then wait for it to dry, sand then put on the fibreglass. This would seem to me to be a good way of preventing air, trapped in the wood, from forming bubbles in the fibreglass layer. I also thought that if you only let the first coat of epoxy go tacky and then laid the fibreglass onto this, the fibreglass would then be held in place by the epoxy and you could work out the wrinkles and not have it move around. I have not tried this just wondering.
Also while i'm here some more stuff about plywood.
I have been looking around at many different types of plywood trying to find some that is suitable for kayaks. The first thing I found is that it is nearly impossible to get plywood that has equal thickness plys on the inside and ouside.
After much reading of info on the net I have found that most plywood has thinner ouside plys (3 ply) so that it has the same strength and flexability in both directions and indeed the Australian standards for marine ply seems to state this.
Has anyone found gaboon plywood with equal thickness plys?
Last weekend while at a very large hardware store in Sydney looking at their Lauan plywood I noticed some other 4mm plywood called structural or bracing ply. This plywood has equal thickness plys, 'A' type bond but only 'C' grade faces i'm not sure of the type of wood but it is a reddish hardwood that will look very nice when varnished. I am sure I could get enough good faces out of the plywood they had but I rang another plywood supplier to see what was available. The place I rang said they have 4mm structural plywood with 'B' grade faces at 2700mm x 1200mm.
So I plan to go and see what it's like on the weekend and if it's OK buy a few sheets. I also discovered that not all exterior plywood has 'A' bond, it could only have 'B' bond. But all Aust. standard structural plywood has 'A' bond and known structural properties and I think it is a good choice for a kayak.
Any thoughts on this?.
OK time to get back to work.