1984 starcraft islander

[Scott Danforth]

Possibly pretreat with xylene or acetone.

doesnt touch the foam, however will sit in low areas creating a fire hazard.

 

[Sharpie223]

I wouldn't expect the solvents to melt the foam, but if its polyurethane foam, xylene should degrade it, possibly allowing it to release easier. This is assuming that you are removing all foam, I'll admit I haven't read closely enough to see if that was the case here or not. Either way, make sure it's all gone prior to using the boat.

 

[Neschenbrenner]

I'd recommend a nylon cup brush, the bristles are easier to work in than wire, and don't shed like wire. For something relatively soft like foam, the wider bristles should make quicker work as well.

A pressure washer might work as well. Possibly pretreat with xylene or acetone.

I've been using a nylon brush works great.

 

[Neschenbrenner]

Making progress

 

[racerone]

Using strong solvents may not be a good idea.----If you have sparks for any reason it might go " woosh " around you.

 

[Neschenbrenner]

Idk if you can see it in the picture but theres just a little foam I can't get around the ribs and stuff like that.

 

[Sharpie223]

Maybe try a stiff bristled steel hand brush?

 

[Neschenbrenner]

What's the best way to find leaky rivets? Also should I pull the gas tank out.

 

[racerone]

Likely a good idea to pull it out for inspection / leak test.

 

[havoc_squad]

What's the best way to find leaky rivets? Also should I pull the gas tank out.

You're this far into it already, do you want re-work later to have to pull it out if it leaks after putting the floor down?

Yes, you do want to pull the gas tank for inspection. If there are no critical corrosion issues or cracks in the inspection, cap the ends and pressure test it 2 to 5 PSI max I believe (Low pressure, it's not an air compressor tank) to make sure it doesn't leak.

 

[Neschenbrenner]

So how worried should I be about these pits there's not a ton but there are few here and there.

 

[Neschenbrenner]

Also what is the trick to getting the fuel tank unstuck?

 

[Sharpie223]

Where are the pits located? That will determine what level of remediation is needed.

Also how deep?

 

[Neschenbrenner]

Where are the pits located? That will determine what level of remediation is needed.

Also how deep?

They are randomly located under where the foam was. None are to deep. Maybe like half a pinhead.

 

[Sharpie223]

Hard to say.

No matter what I would use the nylon brush to clean out the pits, maybe acid clean, and then fill with a fortified epoxy.

If the pits are over a keel strip, I wouldn't worry any further. If they are deep or in a seemingly high stress location, I'd look into patching. Deep and high stress become subjective unless you really want to dive into calcs and modeling.

 

[Neschenbrenner]

I

Hard to say.

No matter what I would use the nylon brush to clean out the pits, maybe acid clean, and then fill with a fortified epoxy.

If the pits are over a keel strip, I wouldn't worry any further. If they are deep or in a seemingly high stress location, I'd look into patching. Deep and high stress become subjective unless you really want to dive into calcs and modeling.

Is there a specific epoxy you would recommend?

 

[Sharpie223]

Honestly, I should modify my previous comment. My main concern with a pit is if it's large enough to cause the base metal to be weak. Since there are holes all through the boat, if it's not at a riveted joint or an obvious high stress path, it probably won't be a concern.
The second issue is corrosion likes crevices, so it creates a spot for further corrosion. This is where I would want to seal it or treat it. Epoxy will seal it, but even flex coatings could possibly peel, allowing moisture to be trapped underneath.
A chemical coating may possibly be better if it passivates the aluminum itself. I think alodine is commonly used for that, but I have zero experience. Zinc chromate primer is used as it will preferentially corrode rather than the aluminum underneath. I don't know how either perform in existing pits.

In my boat, the pits I filled were all the way through, and at the knee brace rivets. I decided to fill with jb weld and patch on both sides. That was just to help seal, the 5200 on the patches does most of the job however. I don't know that I would trust jb weld on its own.

Take my ramblings as things to think about rather than clear paths forward.

 

[Moserkr]

Heres what I used - a two part epoxy type paste and I smeared it all over my transom which had lots of pitting, some almost all the way through. Nothing to worry about as the structure still remained and after nylon brushing the transom, plus cleaning with a vinegar water solution to neutralize the corrosion, it should be all set for the next 40 years. Believe it was recommended to me by others on the forum during my resto.

 

[Sharpie223]

I've been using pc7 as filler in places, which is glass reinforced, as well as some other unknown fillers. It's tough stuff, doesn't shatter when hit with a hammer and hard to clean off the mixing tools. Pc11 I think is supposed to be the "marine" version, maybe more flexible, or made to be applied underwater or something like that.

 

[Neschenbrenner]

Finally got around to doing a compression test on the engines. I don't think it looks good but I'm not an engine expert.

Left
1= 100
3=75
2=110
4=90

Right
1=75
3=90
2=80
4=80