'69 Starcraft Holiday Alum. transom support, cut into or not?

[Sippen]

Hello,
I have near the drain hole in the back, a lot of corrosion on the aluminum. Looks like metal was sitting on it and rust took over.
I'm pretty sure the corrosion would be bad underneath the aluminum angle transom support.. so should I :
- drill out the numerous rivets, clean it up and put new rivets down or
- cut into it, like a 3" opening and try to clean and coat it from there
- or just clean up all around it and not worry about what's inside it?
Being the lowest part of the boat water will always be sitting in this spot.

clean it up, JB Weld it then Zinc Chromate primer and call it a day or add anything else?
(paint would not make sense since it is always damp, right?)
Thanks!

 

[North Beach]

Re: '69 Starcraft Holiday Alum. transom support, cut into or not?

Based upon photo #2 I'd want to get that surface rust off of that bottom. I don't think you have anything to worry about under the flanges since they're set in the Plyabond. So just surface prep and depending on how deep the scar is(off to the side of the flange) you can prob just treat with Gluvit when you do the rest of the seams and rivets and be done with it.

 

[Sippen]

Re: '69 Starcraft Holiday Alum. transom support, cut into or not?

Thanks NB,
I will plan on just cleaning it up and then Gluvit.

no need to prime this area since it's under water most the time Right?

 

[jigngrub]

Re: '69 Starcraft Holiday Alum. transom support, cut into or not?

Priming it won't hurt a thing, and if it was mine I would prime it.

Stagnant water is the primary cause of galvanic corrosion and could be why you have the pitting there.

If you're just doing that one little spot there it's not really worth buying a whole quart of Gluvit, but if you're going to gluvit the whole inside of the boat then gluvit will work.

If it's just the one little spot, do like you said with the cleanup, JB weld, and primer.

 

[North Beach]

Re: '69 Starcraft Holiday Alum. transom support, cut into or not?

Thanks NB,
I will plan on just cleaning it up and then Gluvit.

no need to prime this area since it's under water most the time Right?

Sippen, I think it's pretty much agreed that maybe I took everything to the inth degree on the LL, but I have to say that I didn't have one hull leak and still applied gluvit to all my seams and rivets as a belt and suspenders approach. The gluvit will fill the slight depressions it looks like maybe that rust caused on the flat surface of the metal. And if you have the floor up, I say hit it with the gluvit.

I had many areas like this on both my Islander to cc conversion boat and the 21' mariner that had poured in place foam and salt water damage. I don't see any need to prime the inside of the boat. Do your watertest after you do your wire brush/wheel/sand or whatever you're gonna do. Re-buck any loose rivets, re-watertest, and gluvit the inside seams and rivets with a good slathering of gluvit. If you have some left, hit em again! Priming the inside isn't going to stop leaks and I just feel like it's not needed.