With the first attempt at installing the bow hatch ending in having to remove a bunch of rotten plywood from around the hatch opening, the next step was to rebuild what nature had destroyed.
The Devoe Bar-Rust is great stuff, but I was using the remainder of a can I opened when we sandblasted and primed the hull several years ago. Over time, the catalyst changes color to red (as does West System), which turns the white Bar-Rust pink! Fortunately, according to the company, it doesn’t affect the durability or cure of the finished coating. And since this will be out of sight, it will also be out of mind…our little secret. 😉
Chris craft left these edges uncoated, which allows aluminum oxide to start at the edge and work under the primer and fairing compound, popping them loose. By fully encapsulating the aluminum, as well as the silicon bronze screw heads that I mentioned in the last article, I hope to never have problems with the paint on the foredeck.
So, what I see going on here is: 1) no coating on the edges, which permits water into the grain; 2) doug fir marine ply, which tends to get cracks in the grain over time (and that permits even greater ingress of water); and 3) several layers of plywood of varying thicknesses bonded together to make up the full height. But for the life of me I can’t tell what sizes of ply they are. There’s at least one 3/4″ (and maybe two) but then I also see maybe a 3/8″ and 1/2″…or is that two 3/8″???
Either way, the important thing is to get the final piece I make to be the right height regardless of the combination I use.
The water stains are just surface imperfections. This panel has been dry for 10+ years.
After cutting two panels out of the okume ply, it became clear I couldn’t make the whole structure out of okume because it’s not as thick as 3/4″ doug fir. I wasn’t getting the thickness I need.
I’d been saving some of these plywood scraps for years, wondering if I’d ever use them. Turns out they came in very handy.
I glued, clamped, and then screwed the new panels together, then wetted out the still-tacky Devoe primer on the hatch opening with epoxy. Next, I mixed up some epoxy thickened with wood flour and cabosil and applied it generously to the mating surface of the new plywood, then clamped it to the underside of the deck.
After drilling the screw holes, I taped the bottom of each hole and filled the holes with epoxy mixed with the slowest hardener. Overnight, the epoxy wicked into the plywood around each hole and the hole in the aluminum was also coated. This effectively encapsulates the wood and aluminum, isolating it from exposure to air or any water that might one day seep past the sealant I’ll use.
I also re-drilled the holes to clear out excess epoxy. The holes are 0.004″ larger than the #10-24 machine screws.
I’ll install the hatch glass later. We’re going with tinted glass all around, and I will be ordering all of it at the same time. But I need to get the new windshield frame installed before I know what shape to make the helm station side glass. It’s a process…