Re: BoraCare treatment before resin?
I haven't used BoraCare, but used a home-grown version of it that I used to treat the plywood in my boat. (I didn't glass my plywood as I'm in a dry climate where the wood will dry out) The home grown version is borax boiled in water/glycol antifreeze until the borax dissolves. Boracare could differ from my home grown treatment, probably does, but I noticed a couple of things with the borax/glycol treatment;
1- the glycol dried to a film on the surface of the wood, I washed that off. (too much glycol? probably...)
2- the borax treatment did not penetrate the plywood all that far, ply 1&2 were saturated, but the other plys did not soak up the treatment very much, if at all. The plywood's glue caused a barrier that stopped the liquid from penetrating well.
3- once dried, that stuff is gritty and I hated handling the wood, just felt weird. Nails on the chalk board type of thing.
4- I would do all your machining on the wood before treating it as it leaves a mineral behind that could dull tools. When I drilled into the treated wood it make a weird crunchy sound and I could tell there were minerals in there.
That said, I wasn't 100% confident in the wood rot properties of borax (boron salt, whatever they call it) so I followed up with Jasco Termin8 wood treatment. The Termin8 had little problem seeping into the wood and it easily penetrated through the plywoods top layers,,, through the borax in the wood. Layer 1-2 of the plywood were saturated and layer 3 was spotty, layer 4 hit and miss. Since the Termin8 soaked in without problems, I would imagine fiberglass resin would too.
One thing about borax/glycol (BoraCare), it's not going to seep deep into the wood unless you leave it immersed in the stuff for a long time, the wood will not drink it up after a certain point. (IE: the reason for pressure treating) If you do get it completely saturated,,, it's going to take a long time for it to dry out, possibly warping your wood. Most likely, the middle plywood layers will not be treated and if they become saturated with water, the wood, could, rot from the inside out.
Just my experience,
Again,,, I'm not suggesting that you leave your plywood un-fiberglassed or un-epoxied. I did because wood will dry out in the very dry climate where I live.
