ideas for protecting paint while removing old tank sealer

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mattfitz

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Feb 13, 2010
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I am nearing the end of my '68 Fastback's second rebuild, and have to deal with re-sealing my fiberglass tank due to alcohol in the gas these days, and the fact I want to keep the original tank, and not switch to alloy. I had it sealed 15 years ago, using the yellow colored non-curing PVC type sealer, it was great for many years, but it dissolves in the current methanol gas, which is all I can get now. So I have to re-seal it with a sealer that is resistant to it. I am going with the Hirsch sealer, since they made the yellow non-curing sealer I used originally, and had good results with. I spoke with them and I need to remove the old sealer first, using MKE solvent.

My problem is that I am hoping to try and remove it with the solvent and not destroy my paint job at the same time, which is going to be very tough. I am looking for ideas on how I could protect the finish as much as possible from the solvent which will most surely get spilled to some degree on it. I am thinking of trying to wrap the tank in something?? ...and make some sort of collars for around the filler cap, and the petcock holes, to help protect it while I am pouring it in, and dumping it out. Any thoughts or suggestions on protect the finish as much as possible would be appreciated.
 
Re: ideas for protecting paint while removing old tank seale

That's going to be tough! Methyl Ethyl Ketone will seep under most anything organic (carbon-containing). In fact, you need to be careful as it will dissolve the polyester resin in you fiberglass if left in there too long. After you drain out the MEK blow lots of air inside to dry out all the remaining solvent.

Forget using cling plastic wraps as MEK will attack those almost instantly. Aluminum foil will work, but you need to somehow seal the edges.

I would plan on repainting, but do my best to keep the MEK off the finish. (Plan for the worst and hope for the best.)
 
Re: ideas for protecting paint while removing old tank seale

Ron L said:
Aluminum foil will work, but you need to somehow seal the edges.

I would plan on repainting, but do my best to keep the MEK off the finish. (Plan for the worst and hope for the best.)
Click to expand...

Ron, the aluminum foils is a good idea, would offer a fair amount of protection, provided I can seal the edges, but would at least help quite a bit. I am aware I will probably have to repaint, but hoping I can minimize the damage.
 
Re: ideas for protecting paint while removing old tank seale

I second the alert to the sealer solvent being way more aggressive
than new gasolines, acetone same warning for FG resins.

I'd try to wax as thick layers on 1st as still stays on, foil wrap layers
then use Al or duct or such layers of tape around filler cap and punched through for the fuel taps. Don't leave tape directly on paint over night on in much heat or
you may get sorry finish.

If ya need some abrasive scrapping items inside I'd spring for a tube
of steel bb's and maybe small nuts and washers a magnet on a string
can retrieve later.

I would not trust turning upside down much d/t weeps spills
messing you and stuff up. Also not much need to thick
seal the top side but around filer neck of course.

Plan on days of low hair drier aimed into cap or full sunshine
or low warm oven to cook off solvent out of resin matrix
that will be polluted to some extent,
for best preservation and new sealer adhesion.

hobot - sealing rear tire and riding jacket in good heat today.
 
Re: ideas for protecting paint while removing old tank seale

hobot said:
I'd try to wax as thick layers on 1st as still stays on, foil wrap layers
then use Al or duct or such layers of tape around filler cap and punched through for the fuel taps. Don't leave tape directly on paint over night on in much heat or
you may get sorry finish.

If ya need some abrasive scrapping items inside I'd spring for a tube
of steel bb's and maybe small nuts and washers a magnet on a string
can retrieve later.
Click to expand...

The coat of wax is a good idea, used along with the foil wrap layers, and some foil tape at cap and petcocks. As for abrasives, it has been suggested to me to use short sheetrock screws, as the sharp edge of the threads will cut into the old sealer to help break it up.
 
Re: ideas for protecting paint while removing old tank seale

mattfitz said:
swooshdave said:
What about something like 3M Paint Protecting Film?

http://solutions.3m.com/wps/portal/3M/e ... _Consumer/
Click to expand...

Swooshdave, I think the MKE would likely dissolve the urethane film.
Click to expand...

Maybe, but it might provide a final layer of defense in case there was a pinhole or something in the tinfoil, etc. It's pretty thick, I think, so as long as the MEK wasn't allowed to sit on it there is a chance it would survive.

I would have no faith in coating fiberglass that has had fuel, especially bad fuel, in it already.

fixing-fiberglass-tank-t6227.html

ideas for protecting paint while removing old tank sealer


Unless you did it like Jean did (of course we are still waiting for an update from Jean...)
 
Re: ideas for protecting paint while removing old tank seale

Ah cool, swooheroo, the edgy screws sounds like a winner idea
I'll remember, if ever facing your removal dilemma.

Unless you spill a whole lot just funneling solvent in and then
letting drain out the taps, I don't think you've got too much
to worry about with wax and foil and tape wrap. Might
also wrap a towel taped as cushion in case fumble tank
or resting to settle sealer or solvent.

hobot
 
Re: ideas for protecting paint while removing old tank seale

swooshdave said:
(of course we are still waiting for an update from Jean...)
Click to expand...

I did put in an update, the tank is being used and is very gas tight, the guy I did the work for is very pleased.

Jean
 
Re: ideas for protecting paint while removing old tank seale

Cover it with layers of metal foil tape perhaps. Good luck.
 
Re: ideas for protecting paint while removing old tank seale

Hi all, first I wanted to thank everyone for their great suggestions. This is my follow-up post. Well let me start by saying that it did not work out successfully, while I was able to remove all of the old non-curing PVC sealer and strip the inside back to fiberglass, I was not able to do so while saving the paint finish, and I knew going into this that that would likely happen. I waxed and then covered the tank with aluminum foil as well as used foil tape to secure all the seams and such. It took me about 1.5 hours or so all told of shaking the tank with the M.E.K. solvent in it with some large lag screws to loosen the old sealer. While I was shaking it for that period some would leak out the filler cap and eventually make its way under the foil. This was not a problem at first as the coat of carnuba wax really seems to have protected it where it ran down. The problem comes in that the solvent would get behind the foil and run down tank under the foil and pool up along the bottom of the tank under the foil. When I finished and removed all the foil, the solvent had eaten away the paint about 1/2 up from bottom, all the way around the tank. Everything else was perfect. The wax definitely did its job, but the foil was so well sealed it just held the solvent in there. But the old sealer is all removed, and I am going to re-seal it Hirsch's ethanol resistant sealer tomorrow. Then will re-paint it next week, and then back on the road. (although I think I am going to break down and buy an alloy tank as whenever money permits). Thanks again!

-Matt
 
Re: ideas for protecting paint while removing old tank seale

Yep, pretty typical Commando short cut results I've found.
Worth the lesion trying it and the story to warn us about later.

hobot
 
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