Patching holes and corrosion on a Star craft Mariner

[newriverrat]

I know I'm late to the party. Weld if you can find someone who knows what they're doing--expensive but will last. Depends how many holes. I know people that have braized on smaller holes. I've done epoxy and it held for a couple years, so then just did it again--etching bare aluminum is key. Talk to west systems they've been helpful over the years.

 

[john92673]

I’d check how far the corrosion around the smaller holes has spread first. Chances are, if it corroded enough to eat through, the metal around them is going to be extremely thin and brittle as well.

It doesnt look too bad or feel soft or thin from the outside. No way of knowing how it looks on the inside without pulling up the deck.

 

[DaleH]

I would not epoxy first. The patch buttered with 5200 should work ...

One had better PRIME it 1st ... or this is the result on UNprotected tin!

 

[john92673]

One had better PRIME it 1st ... or this is the result on UNprotected tin!

View attachment 122964

That looks very bad. Wouldnt priming it make the bond to the primer instead of the aluminum though?

 

[john92673]

Im thinking the best course of action is to remove the deck and see what is actually going on underneath. I should be able to do a better job at patching too. Couple questions. Do I have to pull the outboard? I think the wood floor provides some structural integrity but the transom is being supported by the trailer. Also does the wood floring run underneath the interior side pannels usually? I guess if thats the case I just drill out the rivets and re rivet it back together when Im done.

 

[DaleH]

A self-etching primer becomes one with the tin, zinc-chromate was sooooooooooooooo good the EPS banned it! Use the Rust-Oleum self-etching primer for aluminum.

 

[LDUBS]

One had better PRIME it 1st ... or this is the result on UNprotected tin!

View attachment 122964

Thanks DaleH. I should have remembered these pic's from before. I'll blame it on advanced age.

 

[LDUBS]

Good to see Dangar Stu again! He and I used to talk regularly. He came here to the US right as a hurricane hit, so we didn't get to meet in person. Really nice guy and he gave out some very good boat and engine knowledge. He's gotten away from making so many videos, but Dangar Marine has a pretty extensive library of helpful videos for boat owners. A+ in my book.

That being said, he should have filled the pop rivet holes with Sikaflex to keep salt water from eating the rivet from inside and eventually leaking, but he did mention that you can seal it from the outside.

I watch a lot of his videos. He is/was sponsored by Marine Engine, which says a lot I think. On his website (dangarmarine.com), he has this flowchart map to trace down potential issues. A lot of it is way over my head, but it is pretty neat.

 

[john92673]

I know I'm late to the party. Weld if you can find someone who knows what they're doing--expensive but will last. Depends how many holes. I know people that have braized on smaller holes. I've done epoxy and it held for a couple years, so then just did it again--etching bare aluminum is key. Talk to west systems they've been helpful over the years.

I got a buddy who a while ago said he would weld it for me but im not sure how good he is at aluminum. Theres 4 or 5 small puncture holes where I was going to patch it. Theres probably another 4 or 5 pin holes. Im honestly not sure if they are due to corrosion or if the moron before me hit some rocks. Theres some surface oxidation on the outside but nothing crazy. I was poking around the holes and it didnt feel soft. I also hit it with the pressurewasher from an inch or 2 away and it didnt make the hole and bigger. The pressure washer was strong enough to carve a pretty deep gash in the bunks from a few feet away. If I can get the rear deck off and the foam out this weekend Ill know how bad the hull realy is. Not sure if its just oxidation from water getting trapped under the coating undeneath thr hull or its comming from the inside.

 

[john92673]

I forgot to take pictures, but Ive been picking away at whatever all that bottom coating junk is. It took quite a bit longer then expected. Ive been finishing up most of it using a propane torch and a wire brush. I just have to get the small little bits off. Im trying to get everything preped for the spring. Im going to hit the hull with a wire wheel and a sand blaster to clean it for the epoxy bottom coat.