Aluminum Pitting

[Mr. Mom]

Hi Guys,

I know about the pressure treated wood and non stainless hardware could cause pitting. Any idea what this is from? Is it just old age? The boat is a 1974 Starcraft. Thanks.

 

[bobberboy]

How big is the area in the photo? I'm sure I'm wrong, but it looks a lot like a welded area with a lot of voids that was ground down to make the surface smooth. I think pitting makes pinpoints rather than large areas - at least in the beginning stages. ?

 

[Mr. Mom]

It's pretty much all over below the waterline. I'm thinking saltwater maybe?

 

[bassboy1]

Was the boat ever kept in a marina, or in a slip in the water?

 

[Mr. Mom]

I don't know the complete lineage but I'm at least the third owner. I'm thinking it may have been kept in a marina as the boat originally came from rhode island.

Think I should Marine-tex all the pitted areas then use Steel flex or just steel flex?

 

[bassboy1]

Reason I ask about the marina, is that with all the shorepower at the slips, there is a pretty good bit of electrical current in the water, expediting the process of electrolysis. Salt water would further speed this up. Even just being moored in salt water without the presence of shore power, inadequate or nonexistent hull zincs could have allowed electrolysis to eat at the boat.

 

[Mr. Mom]

Ah I see. So is it scrap metal or can it be saved?

 

[Waterwings]

Concur with bassboy on the electrolysis. Seems to be prominent around the rivet heads.

Ah I see. So is it scrap metal or can it be saved?

Hard to tell in a photo. Does the metal seem really thin/flexible?

 

[Mr. Mom]

I'm gonna do some more wire brushing today but the pitted metal seems really solid. I'm hoping that a couple of coats if steelflex will seal her up.

My friend had this boat and it had a couple of leaks. He didn't want to deal with it so I am the proud owner.

Thanks for all the guidance already. Will post more pictures later.

 

[Waterwings]

Looking forward to the pics

 

[Mr. Mom]

Ok, did some more grinding on the boat and just about all the rivets on the bottom have that pitting around them. I ordered a gallon of steelflex and I'm going to hit the rivets with an extra coat before I do the whole bottom with two coats. The aluminum above the side rib looks great. So whatever was eating away at the rivets had to do with the water it was in. I was cleaning up the lower transom and found this applied pretty heavily. Looks like Bondo, what do you think? Should I leave it and steelflex over it?

 

[bassboy1]

I'd take that crap off. It's a matter of when, not if, it comes off on it's own, and even though the steelflex may stick well to it, if it all comes off in one fail swoop, you are left with a mess.

 

[Mr. Mom]

I debated leaving it on but I agree. It's coming off so I know what I'm dealing with. This boat may end up being the poster child for steel flex. Then again maybe I'll sink the first time I hit the water with it

 

[MallardAddict]

get the pits wire brushed out, wiped with a good quality degreaser and fill to level with steelflex. let it harden and sand em down level with the metal and proceed with your planned 2 coats of steelflex. You will be just fine, ask me how i know.......... :shock:

 

[perchin]

Fill with steelflex then sand??? I wouldn't waste my time. just put a couple of coats of steelflex over the entire bottom..... you will find that the stuff self levels and you don't need to pre fill in the pits, and do a bunch more sanding. And just before application wipe down all surface to be applied with Acetone.

Also if you have any loose rivets, buck them ahead of time.

You should update your profile and let us in on your location....... we be nosey :lol:

 

[Mr. Mom]

Thanks for the info guys. The steelflex is ordered and I'll post some more pics during the process. I can't believe how bad this boat is below the waterline. I hope the steelflex works.

 

[MallardAddict]

If the prep work is done properly (wire brushing and wiping with a good degreaser) and the hull scuffed up a bit so the steelflex has some tooth to grip you will be fine.

Remember epoxy wont bond well on surfaces with oils or nothing to grip.

Epoxies in general are very tolerant in application, just mix a bit at a time if your doing it by yourself as once it exceeds its open time (starts to set) it wont spread or level well.

 

[Mr. Mom]

This is going to the junkyard. It's too bad but the metal is just too corroded.

I took some more of the "bondo" off the center rib and discoverd silver dollar size holes under the rib. There had to be about 12-14 rivets gone on the rib due to corrosion. I drilled out a few and did some inspecting and it's just too bad. I'd have to remove the whole center rib and patch underneath and it's just not worth it.

This is my second project boat and I learned a valuable lesson on what to look for with my next one. Thanks for everyones help.