The aluminum boat I am restoring has corrosion where the wood was touching the aluminum on the transom. There is even one spot where the corrosion went all the way through. What is the best solution to this problem? Is there something that I need to do to prevent corrosion from continuing? How do I fix it?
If the wood was pressure-treated, the arsenic salt in the wood could have corroded the aluminum. Or, if the wood was simply holding salt water against the aluminum, same effect, especially if a different metal was in contact nearby.
I'll bet the wood was pressure treated, or one of the other treated types sold for outdor use. (CCA, etc.) Many of these are highly corrosive to aluminum. Better get some quotes on getting the aluminum welded up properly. Then do the wood yourself, using exterior plywood. I'm assuming it's bolted to the aluminum...(Post some pics)....I'm thinking exterior plywood, soaked in epoxy, then wrapped in fiberglass. If you have a bolted in scenario, you could do 2 or 3 sheets of ply on some sawhorses, bond/clamp them together, and then wrap the whole thing in fiberglass. Follow up with a grinder/orbital sander to touch up, drill the holes, let more epoxy be soaked in....and put the thing on there with 3M 5200 sealing the bolts.
Just my thoughts....I'm sure you'll get several idea's here!
Im redoing my boat with the same issues as your boat. It was pressure treated wood causing the corrosion, only I had a lot more than just one hole. Take a wire wheel on a drill and bust through all the powder down to clean metal. Get the large JB Weld "Industro-Weld" and skim coat over all the pitting. Back up the hole with duct tape or something on the outside. I used a pneumatic sander to level it out with the undamaged aluminum. This is definately not the only way to fix this problem, but it seemed to work well for me.
Depends on a few factors. Is this a stress critical area? Do you want it fixed properly and safely? What's the boat worth? An old boat, up on the gunwale I might consider JB weld. But on a transom, or anywhere near the transom/hull joint....no way. I'd clean it up, and at a minimum have it welded up properly. There's many welding shops that can do this for you. I'd definitely take it around to a few and get estimates.
You can weld or laminate a sheet of aluminum to the inside and then install the new sealed transom wood. It is a common problem that has been solved before. Don't Panic.
__________________ "When you see yourself doing something badly and nobody’s bothering to tell you anymore, that’s a very bad place to be. Your critics are your ones telling you they still love you and care." Randy Pausch 1960-2008 The Last Lecture
A couple things about welding. ALL the corrosion must be removed with a Stainless wire brush, or something that won't leave behind impurities like a grinding wheel will. By the time you get through the corrosion, you will have opened up the hole even more, and probably formed a few new ones as you clean out the pits. This will leave very little material to weld to. Plus, I might be concerned about cracking at the weld. The way I see it, unless the transom is so far gone that the metal is in danger of breaking apart, what you are repairing are holes, similar to repairing screw holes. The wood is what supplies the strength. If you want to go through the hassle and expense of getting it welded, by all means go for it. As for me, once its sanded and painted, a JB Weld/epoxy repair is unnoticeable, quicker, cheaper and better
Aluminum Boat with Transom Issue
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