Fiberglass tank cleaning.

dirtymartini · Nov 11, 2011

I found a gummy residue on my carb slides, I fear that the ehtanol is dissolving the resins in the fiberglass tank on the '69 "S" I just bought.

Whats the best solution to clean it out with? I have some Caswell's sealer to line it with when I am done.

Ron L · Nov 11, 2011

As the directions state:

Preparation
1. All traces of oil and gasoline should first be removed by pouring about 1 pint of acetone or lacquer thinner into the tank, and rotating the tank several times to thoroughly sluice the sides with solvent. Dispose of the contaminated solution. Allow to dry.
2. Rinse the tank with Dawn Dish Soap and Hot Water. Rinse and allow to thoroughly dry.
3. Place a hand full of drywall screws with about a pint of acetone or lacquer thinner into the tank and shake them around vigorously for several minutes.
These will dislodge any loose particles of rust, and in the case of plastic/fiberglass, rough up the surface. Dispose of the contaminated solution.
Allow to dry.

Don't leave the acetone in the tank too long. It will begin to soften the polyester resin in the fiberglass.

dirtymartini · Nov 11, 2011

Thanks, Just like the instructions say :lol:

I don't know how old the gas is that was sitting in the tank but is a nasty shade of yellow/brown. There seems to be some kind of sludgy coating inside the tank. I am running to the hardware store now for some acetone.

Hobot · Nov 11, 2011

Acetone is way to go but it dissolves resin too so just hanging it out to dry ain't nearly good enough it Must be Heat assisted for days on end. Not a bad ID to roughen up the inner texture by jostling sharp edgge nuts and a chain to impress them while sloshing the acetone. Pointy screws can lodge I hear. I'd be leary of the soap residues myself as would take so so much water flushing it might stay deep in pours to mess with Caswells or others coating adhesion. Acetone drys water as well as disolves about anything that'd interfere. Its what gets glue sniffers high so beware.

Its takes about 30+ min/2 cig's time of hand tumbling to keep as thick a coating all around till sets up it wont just sag away. Adding heat to cure is also good idea for at least a day or so. Then not a bad idea to do another coat the same way. I used greased wood dowels worked in beyond the tap thread in tank to keep those clear.

Remember you should not/can't store spiked gas too long or water layer collects at bottom.

DogT · Nov 11, 2011

Count the screws you put in and take out. Make sure you get them all. If you use the soap and water, alcohol will mix with water and help evaporate it too without the dangers of acetone, not to replace with the acetone though. I'd take a couple of days between each procedure with heat to dry it. If you have some mechanical way of rotating the tank with the screws, I'd give it a couple of hours, some say the clothes dryer, but I think it would spin too fast.

Dave
69S

dirtymartini · Nov 11, 2011

I gave it the first acetone rinse (without drywall screws) and there is still quite a bit of nasty gunk in there. Some of it seems to have a stringy, rubbey property to it. I wonder if this tank had been sealed before....

Carbonfibre · Nov 11, 2011

If your tank has been "sealed" before, then the chances of anything lasting more than a short time are greatly reduced, as it will be pretty much impossible to remove all traces of the failed sealer, which will be required to mean there is any chance of new sealer adhering.

GRP tanks can be sealed against attack by Efuels, but the only sure way to do this is to remove the bottom of the tank, install a proper chemical resistance layer using novalac VE resin and synthetic veil, and then bond the 2 parts back together.

Use of very brittle epoxy resins designed for high temperature use, may be effective in some cases when used to "seal" GRP tanks, but in most lack of adhesion, and cracking, will mean failure is almost certain to occur at some stage.

cmessenk · Nov 11, 2011

dirtymartini said:
I wonder if this tank had been sealed before....

I think that's a safe bet. That being said, you've got some more cleaning & prepping ahead of you. From what I've read from my esteemed colleagues, acetone can degrade the fiberglass you're trying to protect & seal. IMO, I would switch to lacquier thinner with chain/drywall screws/nuts or whatever....as I believe that solvent isn't as aggressive to the fiberglass as the acetone.

Anyway, once cleaned you must Caswell very carefully...mixing the portions exactly as indicated in the directions is crucial...this can't be overstated. Protect all painted surfaces by "mummy-wraping" the tank with saran wrap. If not a finished paint job, then no worries. Pay particular attention to your petcock areas...I installed the proper diameter / thread bolts into the petcock openings and later drilled out the "plug" to the petcock screen diameter because I wanted the Caswell to "bottom out" in the petcock area.

Be prepared to SLOWLY swirl 1/2 of the Caswell amount contained in the kit with tank between your knees in a very comfortable sitting position. Think about every surface and tilt & pause, rotate & pause, tilt & pause, rotate & pause, etc. etc. until nothing comes out. Properly mixed, the consistency is like honey. Don't do the "pour out the excess" part of the instructions. Seriously, this takes 45 minutes or more to do properly, hence the comfortable sitting position. Once finished, wait an hour and while the first application is still slightly tacky to the touch, repeat with the rest of the mix. Let it cure for at least a week before adding fuel.

I know a lot of folks think coating a fiberglass tank is a waste of time, but mine is over three years now using this technique. It's a long, laborous process, but if you want to preserve a classic fiberglass tank with zero problems, this is the way to go.

Hobot · Nov 11, 2011

Great protocol but definitely *also* heavy WAX the tank before the wrap. I believe one could make a whole tank out of Caswell's Novalac and definitely beefs it up to future impacts.

Carbonfibre · Nov 12, 2011

All the various ideas on how to get snake oil tank sealers to actually work are very interesting. Here's a few things to consider:

1) Using acetone inside a tank which has already been sealed, and may well have suffered corrosion damage previously, will almost certainly lead to early failure of subsequent repair work, as the acetone will tend to leach into any area of the laminate which has been damaged by ethanol, and will tend to come to the surface during exotherm of epoxy sealers, making a good bond pretty much impossible.

2) Sealing products which are too high viscosity to quickly coat the inside of a tank using the slosh coat method, should be thinned and applied using 2 or more coats. The only reason this is not recommended has to do with the want to sell product, rather than anything to do with increasing the chances of a lasting repair.

3) Very brittle epoxy coatings are not suitable for use as slosh coatings inside GRP fuel tanks, for the simple reason that uneven film thickness coverage which will certainly result from applying quite thick material as the manufacturer suggests, are very likely to crack in the thinner areas of coverage as a direct result of the vibration which will occur on a running bike.

4) The performance of brittle epoxy resins as slosh coatings for GRP tanks can be increased substantially by thinning and applying in a 2 stage process, as this will result in more even coverage, and can be further improved by the addition of something like kevlar pulp, which will considerably increase the strength/durability of the cured coating, and reduce the chances of cracking.

5) Finally before choosing any of the tank sealing products, contact the manufacturer and ask for the results of testing they have carried out on their products, and bear in mind the fact that those which cannot pass a simple industry standard peel test under laboratory conditions, are not likely to seal a motorcycle tank against corrosion attack for any length of time.

Hobot · Nov 12, 2011

Hmm, What IF???
One were to soak mats of carbon fiber or such with the Novalac resin and make a whole tank out of it just like any other fiberglass kind? The Caswell kit set up state, in fractions of an inch thickness, may not be as brittle as other examples you are judging by.

When Ms Peel had rear blow out that derimed the tyre as we crested a sharp rise on paved back road it tank slapped with my help so hard to keep from hi siding @ 55 mph it snapped off the stem tab then bent the bars into the coated IS tank to chip shatter 1/4" deep gel coat and powered resin and fractured glass cloth out but did not show even hair line cracks inside. The smooth bar tube bend did this so wound was over inch long by 3/4" wide with the explosive cratering in the center about no.2 pencil impression scale. All's I did was glob bondo in then refinish in Electric Kool Aid for current Peel edition.

I've crashed on Wes's 8 yr Caswell'd HyRyder tank so hard my knee shoved the engine sideways enough to bend the head steady plate slamming chipping inside tank tunnel, but did not leak from the bone crushing impact on 70 mile ride back but did soon after leak on Wes d/t the rubbing action of grinding a bolt into tank. He bent it back and JBWelded the tank a couple years now and we did fine this summer on a total boozed gas trip 900 miles each way with 2 days sleeping in open.

It ain't double blind clinical trial scientific study but lends to my initial impression of Caswell that one could make a whole tank out of it.

mikegray660 · Nov 12, 2011

just to chime in - i've sealed many tanks ( at least 5) with the caswell - and at some point the ALL failed - some maybe 3-4 years but eventually they started leaking again (ruining paint jobs) or the gas reached the fiberglass and dissolved it. maybe if the tank had never seen gas it may work.

the worst part is the dissolved crap builds up on your intake pathways - gumming up the carb - but more importantly coating your intake valves too. I had a value stick open from this accumulation and it caused all the horrible things one might think of when this occurs. SO while i would say if you got the stuff use it, but watch it closely and start you search for a metal tank to avoid the eventual "remelt-down" or you may have consequences that result in some serious repairs and $$
m

Hobot · Nov 12, 2011

Yes Mike I'm biting my lip on remembering your bad experience after a teasing delay period. There are unknowns here on state of tanks before the coat and who knows what but not good news as I assume you did em up as right as possible. ugh. The suspense knowing engine at risk too. Damn corn lobby all the way back to the industry that profits at our expense.

mikegray660 · Nov 12, 2011

hobot said:
Yes Mike I'm biting my lip on remembering your bad experience after a teasing delay period. There are unknowns here on state of tanks before the coat and who knows what but not good news as I assume you did em up as right as possible. ugh. The suspense knowing engine at risk too. Damn corn lobby all the way back to the industry that profits at our expense.

damn hobot - i understand your post and agree with it - whats the world coming too! :mrgreen:

dirtymartini · Nov 12, 2011

Will a standard steel Roadster tank be the same size and shape as the tank on my '69 "S" ? Maybe I should think about this if I am going to repaint. Maybe a class action lawsuit against the ethanol industry is in order.

Carbonfibre · Nov 12, 2011

mikegray660 said:
just to chime in - i've sealed many tanks ( at least 5) with the caswell - and at some point the ALL failed - some maybe 3-4 years but eventually they started leaking again (ruining paint jobs) or the gas reached the fiberglass and dissolved it. maybe if the tank had never seen gas it may work.

the worst part is the dissolved crap builds up on your intake pathways - gumming up the carb - but more importantly coating your intake valves too. I had a value stick open from this accumulation and it caused all the horrible things one might think of when this occurs. SO while i would say if you got the stuff use it, but watch it closely and start you search for a metal tank to avoid the eventual "remelt-down" or you may have consequences that result in some serious repairs and $$
m

Lots of marine engines have been completely destroyed by dissolved resin being drawn into the intake system through contaminated fuel. If they are followed to the letter the ridiculous micky mouse application instructions that come with the snake oil "sealers" will almost certainly result in early failure. However bulking out the sealing resin with something like kevlar pulp, and applying it thinned in a 2 stage process, will probably increase the chances of a long term repair by around 200%!

cmessenk · Nov 12, 2011

Carbonfibre said:
All the various ideas on how to get snake oil tank sealers to actually work are very interesting. Here's a few things to consider:

1) Using acetone inside a tank which has already been sealed, and may well have suffered corrosion damage previously, will almost certainly lead to early failure of subsequent repair work, as the acetone will tend to leach into any area of the laminate which has been damaged by ethanol, and will tend to come to the surface during exotherm of epoxy sealers, making a good bond pretty much impossible.

I agree with statement 100%...that's why I would stick with the lacquer thinner, and not use acetone.

2) Sealing products which are too high viscosity to quickly coat the inside of a tank using the slosh coat method, should be thinned and applied using 2 or more coats. The only reason this is not recommended has to do with the want to sell product, rather than anything to do with increasing the chances of a lasting repair.

The word "quickly" here is the key...this process is not quick when perfomed correctly and takes hours to perform.

3) Very brittle epoxy coatings are not suitable for use as slosh coatings inside GRP fuel tanks, for the simple reason that uneven film thickness coverage which will certainly result from applying quite thick material as the manufacturer suggests, are very likely to crack in the thinner areas of coverage as a direct result of the vibration which will occur on a running bike.

4) The performance of brittle epoxy resins as slosh coatings for GRP tanks can be increased substantially by thinning and applying in a 2 stage process, as this will result in more even coverage, and can be further improved by the addition of something like kevlar pulp, which will considerably increase the strength/durability of the cured coating, and reduce the chances of cracking.

If done correctly, you can achieve an even coating if you take the time....my thoght is that few folks do.

5) Finally before choosing any of the tank sealing products, contact the manufacturer and ask for the results of testing they have carried out on their products, and bear in mind the fact that those which cannot pass a simple industry standard peel test under laboratory conditions, are not likely to seal a motorcycle tank against corrosion attack for any length of time.

No disrespect intended, CF, but I'm thinking you should go into the sealing business since you've "been there, done that" with respect to everything about these products. Hell, you could retire early if you could fix everyone's FG tank woes.

dirtymartini · Nov 12, 2011

Acetone with drywall screws today along with lots of shaking....followed by a rinse with hot water and Dawn dishwashing liquid. I think I am going to give it another Acetone sloshing tomorrow followed by another rinse.

Carbonfibre · Nov 13, 2011

No disrespect intended, CF, but I'm thinking you should go into the sealing business since you've "been there, done that" with respect to everything about these products. Hell, you could retire early if you could fix everyone's FG tank woes.[/quote]

Have done some initial testing with a modified polysulphide industrial sealer supplied by PPG, which seemed an awful lot better than any of the ridiculous cowboy products around currently.............

However end users seem to think the snake oils sellers claims are correct and only grasp the fact that they arent after they have followed the ridiculous application instructions (which are not relevant to dealing with GRP) poured in the "sealer", and after a variable period of time, need to look at purchase of a replacement tank!

As outlined in earlier posts its quite possible to greatly increase the chances of a snake oil lasting a lot longer, but this takes a little time and effort, so most end users cant be bothered.

Ron L · Nov 13, 2011

Have done some initial testing with a modified polysulphide industrial sealer supplied by PPG, which seemed an awful lot better than any of the ridiculous cowboy products around currently

I assume you are talking about the polysulfide/manganese dioxide system sold by our Aerospace division for aircraft fuel tanks? I spoke to the tech guys a couple years ago and they told me that it would not be suitable as a "slosh" sealer, but is designed as a brush on. Sounds like if you take the tank apart this would work. Keep us informed with your testing!

Fiberglass tank cleaning.

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