I’ve got some questions and need some advice before starting, mostly on the vacuum bag process, I’ve read alot of the threads i could find here.
I was thinking to put 2lb glass top and bottom on the core like a regular lam coat. Then epoxy gluing two bands of the rail build up, then vacuum bagging the top and bottom plywood. Then epoxy gluing the three-four more rail bands, shaping the rail bands, and finally epoxy glassing with 2lb glass top and bottom.
Is putting the lam glass coat on the core not needed? should the epoxy and glass between the core and the plywood deck just be part of vacuum bagging the plywood skins on?
Does anyting thing seem wrong with the materials or the sequencing?
Gonna go for it, huh? Don’t forget that shape comes first. You don’t want to allow any limitations in your build method to get in the way of getting your shape right.
If it was me…
I’d skip the plywood altogether. I’d use a heavier core and lighter wood . Like a light density PU blank to cut off any difficulties with expansion or water instrusion, covered with 1/16th planks or even veneers. That way you’ll be better able to manage the compound curves.
If you bag the skins on with non-woven veil or perhaps some of that liteweight sports netting the board won’t be so stiff. CoreCork is another reasonable alternative that a lot of people like. If Stretch can make a Mavericks gun with a veneered bottom and cork deck/rails then that demonstrates considerable potential for that combo.
1/8 ply is going to give you trouble. It will fight you as you try to get it to conform. Also here’s something about wood; it swells when you wet it. Water or epoxy, it is going to swell. And as it swells, it swells more in the areas that absorb more fluid. That’s why wet wood warps. So whatever wood you use, it is going to need the most uniform tight grain available, to absorb evenly. Thinner wood will fight you less and absorb more evenly.
The ply I’ve got is 1/8" cherry. The face going down is “C” grade. Would you put a coat of sanding sealer on the plywood first?
I was thinking to make the rails 1 1/4" so the wood doesn’t have to wrap down the rails much. I could thin out the plywood by planing it down, or cut it into strips like 6" wide. I figure if I bag it dry first I can see how well the plywood will conform to the shape.
[shrugs] The beauty of building your own is you get to follow your own path and do your learning on your own terms.
FYI - The most common complaint about boards built with 1/32nd veneers top and bottom is that they’re too stiff, and that’s without the solid wood rails. However, they are pretty tough in terms of weight/strength.
Even veneers sometimes need relief cuts in order to wrap the compound curves of the deck - and that’s just one layer with no cross support.
you be better off resawing some lumberyard cedar or redwood fencing into 1/8"- 1/4" and thickness planing it down into something useable
the cross grain buildout of ply makes it a bad choice for compound curves
marine ply is popular for hollow builds like paul jensen and marke showed us but it creates an undue heavy build over foam
like greg and bert have said, even standard veneer is many times thicker than a sheet of fiberglass it’s a natural but much stronger composite bulker that’s all
bamboo, willow, cypress, cedar, paulownia or any saltwater resistant mangrove tree wood
but sometimes its better to find out these things on your own
After considering the comments and reading more I decided to do a straight ahead PU construction. I’ll work up to the more elaborate builds. I really do appreciate the advice.
