Topic: Paint Disaster

[iron_worker]

So my lovely paint job went from immaculate:



...to this...



..to THIS  ...



What the *&&%?! It started as a tiny bubble right under the gas cap which I was pissed about but figured I could deal with because at least it was covered by the cap. Then it spread ... and then it spread more and quickly!

I didn't put 2 and 2 together but each time I filled up my tank is when it got worse quicker... I think I finally figured it out today. Is it possible to have a pin hole leak where your filler neck attaches to the main tank body?

My only other guess is my that maybe my vent is plugged. It's pretty warm out today and could hear it sort of releasing pressure. Would that cause this?!

I'm not really too sure where to go from here. Any suggestions? Obviously it needs to be repainted (ugh... was a huge pain in my @ss dealing with a POS paint shop the first time round).

Pretty depressed right about now.

IW

[ekpent]

Gee sorry to see that for you. Might be leaking around the cap seal also. Did the body shop give you any assurances about it being gas resistant at all and was it clear coated over the paint ? What kind or brand of paint is that ?  I like you would be very depressed about it also.

[calj737]

Sorry to see that happen. I see 2 issues: vent as you suspect, or there's a leak in the neck where it is brazed to the tank itself. Either of these is causing the contamination. The other problem I see is a lack of adhesion of the paint to the primer. Even with that exposure to fuel, I'm surprised to see the paint bubble away so drastically.

My opinion, they either sanded too smooth between primer and paint, or used an inferior paint material and it didn't bond well between the two.

[iron_worker]

Anyone ever hear of a leak at the filler neck connection before?

How does one check if the vent is clear/working?

I am sure it was cleared. The paint is the factory paint from a Rousch Mustang actually.

Don't laugh but what actually happened was the first time they painted the colors backwards the first time (red around the Honda logo and black on the main body of the tank ... ugh ... He tried to save the decal since he'd already screwed up the original one and had to pay a custom decal shop to make another one when he probably should have just sand it all down and started over. I'm guessing they rushed the prep and that's why the red is coming off so easy now. Oh ya and they took 4 months to do the job when they said it would take a couple weeks.

Did I mention that they suck and I hate them? 

IW

[calj737]

If your tank is like mine, '74 550, then yes, I've seen them leak. Can be caused by corrosion, chemical dips, who knows, basically, the neck is a thin tube inserted into a stamped shell, then brazed (I believe) from underneath, then the bottom appears to be seam welded or crimped. But I recently cut the neck out of another tank, and this appears to be the process used.

I wasn't suggesting the Rousch Red was a bad color, only offering that maybe they used a cheap brand of paint and matched the color you wanted. You never know.

Your explanation of color over color leads me to believe they did not scuff the surface sufficiently and that is leading to the adhesion problem. The vent is the seal under the cap. You should remove the cap, and check that it's in proper condition.

I'd hate them too if they took 4 months to paint my tank and got it wrong while doing it-

On your side, and feel for you!

[ozpacman]

I wouldn't be to hasty in blaming the painter.  You clearly have a fuel weep that is seeping under the finish and lifting it off.  All the paint preparation in the world is not going to stop what's occurred on your tank.

A mate of mine once removed the fuel tank of his then new Harley and sat it on a towel which he then folded back over the tank to protect it while it was off the bike.  The fuel inside the tank slowly leaked out around the equaliser tube at the lower front of the tank as he hadn't tightened the clamp sufficiently.  The fuel slowly seeped onto the towel which then wicked upwards and left one side of his tank looking exactly like the top of your tank.

Like you - he wasn't too happy either . . .

Russ

[Killer Canary]

Your painter would have been wise to clear coat beyond the paint in that area. Looked very nice for a while.

[iron_worker]

Ya I guess the clear is probably fuel resistant but if it really soaks on there it's only a matter of time.

My theory as to what happened is this:

It didn't used to leak fuel before I painted it but during the rebuild I stripped out the failing liner and soaked it in vinegar to remove all the rust. So it probably had enough rust and/or just enough sealer left up there to keep it from leaking.

So the question is ... is it cheaper to try and fix (have it rebrazed?) this one or find a new tank? I actually happen to have another tank (with an extra crappy paint job).

IW

[iron_worker]

Your painter would have been wise to clear coat beyond the paint in that area. Looked very nice for a while.

Yes, this was another question I had. They had painted right up and over the top of the filler neck which of course started getting real soft as soon as I filled it up the first time. I scraped the paint back so it would start outside of where the rubber gasket seals.

What is the proper place to end the paint at the filler neck so it isn't harmed by the fuel?

IW

[Killer Canary]

I only tape off the sealing area and clear the entire neck, sans paint. On a proper planet, your painter would make it right. They should have known that this would happen.

[seanbarney41]

I doubt the neck is leaking.  If it was, you would see the primer coming off too.  I think this is caused by the cap venting properly, i.e. the gas fumes have triggered the paint to fail because of improper adhesion between the primer/substrate and the base coat...or a poor quality primer.  Every paint job I have seen since the advent of ethanol gas with paint on the filler neck has failed here...but the damage usually has stopped at the filler neck.

[calj737]

It didn't used to leak fuel before I painted it but during the rebuild I stripped out the failing liner and soaked it in vinegar to remove all the rust. So it probably had enough rust and/or just enough sealer left up there to keep it from leaking.

Here's your answer. If it were me, I'd re-line the tank, then have it re painted. I personally have had no problems with painting the neck, but I do strongly recommend NOT painting the lip that seals against the cap seal.

I differ on the cause than some others, I believe the leak is from the neck seam. Fairly obvious from my perspective as to where it began and where it's continuing. Once you drain the tank, dry it inside and out fully. Then, apply tissue around the neck at the bottom. Fill tank with water and see if it is indeed leaking. Simple proof. If it leaks, line it.

[iron_worker]

The reason why I think the neck is leaking is because this morning when I checked it out the paint had really peeled back and it was actually wet looking and you could smell fuel on the outside. I had filled the tank up the night before and it was right up .. the fuel level was up over the filler neck/tank connection towards the back. 

IW

[iron_worker]

It didn't used to leak fuel before I painted it but during the rebuild I stripped out the failing liner and soaked it in vinegar to remove all the rust. So it probably had enough rust and/or just enough sealer left up there to keep it from leaking.

Here's your answer. If it were me, I'd re-line the tank, then have it re painted. I personally have had no problems with painting the neck, but I do strongly recommend NOT painting the lip that seals against the cap seal.

I differ on the cause than some others, I believe the leak is from the neck seam. Fairly obvious from my perspective as to where it began and where it's continuing. Once you drain the tank, dry it inside and out fully. Then, apply tissue around the neck at the bottom. Fill tank with water and see if it is indeed leaking. Simple proof. If it leaks, line it.

I would like to avoid a liner if possible but maybe not an option. Wonder if I could get a rad shop to braze it? They'd have to steam clean it or something first I guess to avoid a large boom. lol

[calj737]

To braze it, they'd have to do so on the outside. The neck is inserted into the hole, and they may not be able to do it fully.

Drain, wash out with soapy water, rinse well with clear water, then run acetone through it. 20 minutes later, you could drop a match in it safely.

You could only install a liner on the top underside if you're averse to having a liner on the entire tank. That would seal the leak and leave the tank in bare metal. Or braze it. Whichever.

[iron_worker]

I just have read a lot of liner horror stories and I know how much of a PITA my failing liner was to remove ...

Bah, what a #$%*ty problem to have.

IW

[calj737]

I've done about 6 tanks with them. 4 had a prior liner in them. I filled with Acetone, out came the liner super easy. Of the 6 I've lined, I couldn't be more pleased with foolproof results. I've used RedKote on 2, but switched to Caswell on last 4. I prefer it for installation and curing. Comes in a clear or colored as you prefer.

[iron_worker]

Well that would have been good to know before. lol I used paint stripper and steel wool on the end of a coat hanger... it took several rounds of that.

Well maybe I will look into the Caswell kits. Thanks for your help.

IW

[Garage_guy_chris]

i had a CB450 tank leak on one of the pinch / weld seams and it did exactly that, it bubbled and lifted the paint and primer. 

[754]

Not trying to slam you, but the only time of would ever fill a tank right up,  is if I immediately. Got on it, and ran it enough to lower the level..
 
 One reason. Would be that cool gas coming out of the ground can expand as it warms..
 Any tank filled right up, can lose fuel easier than normal

[iron_worker]

Ya I guess I didn't really think about that. I usually try to keep it topped up to keep the rust at bay... apparently you can have too much of a good thing! 

IW

[AJK]

I agree with everything CalJ said regarding the filling with water to test, except i would prefer to test with a tank of fuel than water, because fuel being thinner will find gaps that the water may not.
 It also looks like the old liner was perhaps sealing something around there, and by stripping it out, it may have revealed the hole it once sealed. Just a possibility anyhow.
  Also fully agree with 754 on the fuel level on during a fill-up. Last week, i filled it quite near the top, then rode it home. Half an hour later i smell petrol (gas) in the garage, look around and the top of my tank is all wet. I don't usually fill it that high but this time i must had been extra keen. Make sure you leave a sufficient air gap, or like 754 says to take it for a good & lengthly ride. Definitely won't do that again.
  Yeah, that outcome would depress me as well. If your 'other' tank is servicable, i'd just do a quick and dirty spray job with some cans with it while you get your original re-done.

[lucky]

Did you put MAX2K two part clear over it to make it fuel proof?
Is the tank lined?

[Gordon]

Your painter would have been wise to clear coat beyond the paint in that area. Looked very nice for a while.

That's the first thing I thought of when I saw the picture, too.  If the color and the clear both go right to the edge of the filler neck, the gas will wick its way under the clear through the color. 

[Trad]

Did you put MAX2K two part clear over it to make it fuel proof?
Is the tank lined?

I love that stuff.