I have no ability to store my boat out of the weather. I normally winter over by setting by my Dory on blocks upside down, covered with a tarp. And then I fight with the tarp all winter long to keep it from blowing away and taking my Dory with it. I’m not joking we have some nasty winds here. This year I skipped the tarp; I guess that was a bad idea. I notice the other day an area where the paint was bubbling up away from the boats surface. Sure enough water has seeped into a plank and has delaminated a section of the ply. My plan for repairing is this, sand the whole boat to prepare for a fresh paint job. I am going to have to “sand through” the damaged plywood. It is still wet and I just think it had better go. Get down to hard dry wood. Re-coat the damaged area with 3 coats of un-thickened epoxy. Here is where I need some suggestions. My first thought was to mix up some pretty thick wood flour/epoxy and build up the area that was sanded away. Then I started thinking about Bondo, would that be a viable alternative? I question because I don’t know how much epoxy I have on hand, and I can easily source Bondo locally. After the repaint, would Bondo be water safe?
The internet advises that the polyester resin in Bondo is not recommended for application over epoxy resin.
You could probably achieve similar results with micro-balloon thickened epoxy. If you were able to secure enough epoxy, you would have one less thing to worry about.
There are several folks here with more experience than myself. Give them a few days to weigh in.
Whichever method you choose, please repost here on your experiences.
i have done wooden boat repairs in a lot of differen contexts (core replacements, wooden kayak repairs, plywood bulkhead repairs in fiberglass sailboats, etc) .
my first reaction to your post is, hold on the sanding, get things out of the wet and let it dry out..then evaluate your next steps.
sanding down to ‘dry’ is not a concept i have ever really heard in the repair community. i am not saying that we might not recommend removing some pieces, but we evaluate that after everything has dried out and new moisture is off the table.
there are some techniques, for example that can repair plywood that delaminated due to moisture…after it is dried out…without cutting the pieces out. so you don’t want to take those options off the table prematurely.
anyway, my recommendation - let it dry out and post some pictures of what you have…and we can give good advice.
Definitely let it dry out as Howard says before proceeding. Beside letting you evaluate the situation, sanding wet wood is a nasty job and can force water into the dry parts.
RHP is correct that because of the polyester resin (instead of epoxy resin) Bondo is not really suitable for wood repairs that will get wet. Polyester resin is porous because of the channels formed when it releases the styrene gas that catalyzing it produces. If it gets wet water will soak through. Polyester resin also does not stick particularly well to anything but itself, so it will eventually separate from the wood. This is why commercial boats are covered in gelcoat (to seal the pores) and are manufactured with so much chopped glass embedded in the resin (to form a solid mass). This is also why there was such a rot problem with older boats that used wooden cores for bulkheads and such. If there was any pathway at all (like scratched gelcoat) the water would find its way into the cured resin and spread throughout the boat. The same would eventually happen with your Bondo patch, unless it fell off first. So stick with epoxy-based fillers.
Epoxy/woodflour would make a strong patch in terms of abrasion and compression resistance, but it would be difficult to sand. Epoxy/phenolic microballoons are easier to sand but not as resistant to abrasion. Neither stand up well to torsion and both, especially microballoon, are vulnerable to shear. They should not be used for structural repairs on their own. If you do end up using them, they should be covered with a layer of glass cloth to provide tension and torsion.
In my experience, the best repair method is to cut away the rotten wood and grave in a new piece. With S&G boats that usually involves less work than on traditional wooden boats because the inlaid pieces can be held in place with gap-filling epoxy/woodflour putty and fiberglass. With a painted boat the matching piece does not need to be as exactly shaped, either, since any fairing compound and such will be hidden by the paint. Cutting away the entire thickness of the plank makes sure that you don’t have any hidden rot festering under the paint.
So that’s my thoughts, worth triple what you paid for them As Howard and RHP say, please keep posting your progress. It really helps others who may have this proble in the future.
Thank you all for your advice. I will allow things to dry before proceeding. Bondo is off the list! I was watching a you tube video of a fellow repairing a 100 year old workbench. obviously no plywood, but anywhere there was a crack he would run glue down the crack and used compressed air to force the glue inward. I may give that a try. Heck, I can’t make it much worse at this point! So the boat will sit in my garage, my wife’s car will sit in the boats place outside. Give it a few weeks to dry and I will see what I can do.
I started the repairs today; I sanded down the paint on the side damage. I have a good plan for the repair. I didn’t mention in this post that there is actually 2 points of damage. The 2nd damage, while it looks more dramatic is a bit more straightforward repair. While I was working, I was trying to figure out how this damage happened. Then I remembered, 2 seasons ago I had an idiot in a ski boat slam into me and pin me between her boat and the dock. She was kind enough so shout “sorry” as she motored away. At the time I didn’t see any real damage, but I am seeing it now. I made a mistake that day, I have always said I would never go to the lake on a weekend or holiday. Too many stupid people on the water who have no place in the driver seat of a boat. I have not done it since and will never do it again.
As Howard and RHP say, please keep posting your progress. It really helps others who may have this proble in the future.
