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HI does anyone know what may cause the paint to blister on the fuel tank - there does not seem to be any fuel leaks just large air bubbles under the paint. If you squeeze them they flatten out but now look a mess as the paint seems to have stretched and leaves a crease when flat.
 

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has it been repainted? I do a lot of custom paint and also the assistant manager of a dealer body shop. My Daytona is blistering...it was blistering when I got it I could tell whomever did the paint job busted through the factory sealer that seals the tanks. Even though I sealed it the best I could I still have some blistering coming up again, I have reserved myself to buying another tank. Years ago when I used to race ATC 250R's we would redcoat the plastic tanks then paint them, that was the only way you could make paint stick to the polytheylene as its a breathable plastic and the gas fumes would go right through the tank and blister the tank. Im thinking I may have to do that to my Tona tank to get it to stay finaly.
 

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I dont think it has been re painted but it is a cheap replacment from a scrap bike as mine got a small hole in it - The hole in this tank is now reapired but its got scratched in storage so would need painting anyway - what is the paint you used to seal yours.
 

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The only luck ive had with making paint stay is sealing the inside of the tank (redcoat) that way the fumes don't permeate through the plastic. On the outside Ive only had luck using waterborn sealers, but even then Ive had failures. Honestly I wish I knew what triumph or acerbize use on the tanks prior to painting.
 

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if you guys don't drive your bikes every day like I do mine, you should try removing the tank and all the components and sealing the inside with redcoat letting it dry then refilling with gas and see if the blisters stay down or get worse.
 

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It's caused by ethanol gas - the ethanol pulls water from air and it is absorbed into the plastic causing it to swell and deform; there is a filler 'Skin' on the outside and this is what cracks & flakes because it doesn't flex when the plastic expands & contracts
You need to drain/dry tank then line with something like Caswell Plating epoxy kit
Then get rid of the cracked flaking skin, re-level with filler then paint
I just used the Caswell kit myself to seal tank before painting - it works extremely well
It was probably a little cool when I did mine - i would advise a little warmer environment would be better to help the mix flow more readily throughout the tank


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Decosse is the caswell a two part kit? I havnt had luck with two part kits in plastic tanks, that's why I suggested redcoat....it kinda stays flexable.
 

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I think I'll just ride her, Florida allows year round riding. The bubbles really don't bother me on a 78,000mi bike....maby someday a complete paint job then I'll epoxy the tank.
 

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I just purchased a 07 Bonnie and it has a nice quarter size sem-soft blister about 4.5 inches from the filler opening. It is the only blister on the tank. A painter stated that he thinks it is q pinhole in the top of the tank. The inside is clean but the stock lining does show it's age.
My question is: would a stripping of the tank and a epoxy lining cure a pinhole?
 

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Yes, the Caswell is excellent
It won't do anything to rectify the existing blisters on the outside - that is actually a 'filler' coat over the plastic that bubbles and ruptures from the swelling and only fix there is to sand, re-skim that section and re-paint. But the Caswell should prevent the issue from recurring as it DOES create a barrier for the plastic from the gas. I did my own tank a few years ago.
 

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I've seen a few posts about this over the years. Blistering (especially under the Tiger stripes) seems to be pretty common
 

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Having had about 4 tanks blister.....apart from accelerated rusting......ruined vac tap diaphragms.....split float O rings.....snapped rubber fuel lines......leaking floats......leaking rubber tipped float needles......the Ethanol destruction list is endless. Plus the price of Corn Flakes has gone up, as they are effectively growing food to make ethanol to charge us more to wreck our bikes and classic cars. Very Eco.
Caswell tank liner is only one found that works. Have to rub down tank to let it breathe. Very strong detergent/water wash out of stripped tank. Very thorough. Rattle sharp items about inside to scuff it up. Let it dry thoroughly.......if warped (as on Daytona 955i) let it sit a long long time for it to return to shape. Then Caswell....i dont skimp so use the big kit to make sure get 100% cover over the inside.....see many youtube videos. Make sure sort the tap holes and pump openings etc, the stuff is very hard when set.
Then get tank re-paint by good man who knows what primers etc to use.
Never put ethanol in bike!!! At the moment Esso Supreme Super Unleaded is ONLY fuel with no ethanol (except in Teeside, Devon, and Cornwall. That may even change next year.....even after Brexit.....the greens are talking 15% now!
If that happens will have to go back to stripping it out again. See youtube again. Distilled water (with some food colouring to help) big shake, let stand, drain off, through Mr Funnel into tank = no ethanol. Still use premium fuel as most will still hopefully be at 5% level anyway.
Use Sta Bil in tank so fuel lasts for 2 years, instead of 3 months, plus (if do have ethanol) at least it stops oxidation.....but plastic and rubber will still get duff.
Triumph, Buell, Ducati. All suffer worst. Fibre-glass cafe racers. If have very low mileage classic may have to think Aspen fuel, or Avgas etc. £16 a gallon....also no benzine to give you cancer.......ask the chain saw and strimmer lads where they get theirs from. Any sensible tree surgeon or gardener puts it in their gear, as they inhale the fumes/exhaust all day.
See what Jay Leno thinks of Ethanol......he only uses canned fuel now. Has had literally hundreds of his classic collection in bits due to it !
In Canada they used to have an Ethanator kit as on youtube
that makes ethanol strip a doddle, and in quantity. Never found it for sale. Tried the phone number on kit, but no reply. Someone out there will wipe up if makes a nice bit of kit like that. One aviation guy in Canada made a huge thing like a butter churn. Massive glass vessel on a spinner, with drain on bottom. Saved buying Avgas.
Can be distilled out, but that needs proper safety/industrial approach.......i would buy it! Friends in France and Holland can readily buy non-ethanol fuel at certain stations, just a tad more expensive. We cannot......except for Esso.....for now.
 

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I thought about putting a ball valve on a jerrycan, on top opposite the fill hole, and using this procedure with a bit less fuss. Same thing: add the water, shake and then stand the jerrycan up with the ball valve down in a bucket with a cutout or a stand where you can reach the ball valve, and drain off the ethanol/water.
You could probably modify the air vent or fill opening to take the valve assembly pretty easily.

If you always get 4 gallons / 15 liters and then add 1.5l of water, then drain off 3.25l or so you should be OK.

Thankfully a station with E0 opened up a couple miles from me so it got easier for me to keep small amounts of fresh E0 on hand for small engines and winterization.
One of my Tigers, someone must have stored with a small amount of E10 in the tank and the fuel pump assembly corroded badly.
 

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Some years ago I spoke to Triumph tech about this issue with bubbling under the paint on my 2005 955i Daytona.
Their opinion seemed to be that it was caused by condensation during winter storage.
Since then, I've always cleaned and polished the tank, and then covered it with clingfilm before laying the bike up.
After doing this, I've not had a repeat problem with bubbling.
As an aside, some years ago, I was going to buy a used Triumph tank. When the tank was taken out of the shed where it had been stored over winter. It was covered with bubbles under the paint. The pump and filler cap had been removed.
The owner of tank was more surprised to see the bubbles than me. (or so it seemed at the time).
A sprint St I know, was kept in a wooden lockup during one winter. The shed roof sprung a leak, and the shed interior smelled of damp. The fuel tank under a cover had bubbled all over.
My spare fuel tanks, kept in my house, once the vapour has evaporated, have never had problems with bubbling.
To my mind, the problem seems more to do with condensation control rather than ethanol, unless somone's conducted controlled experiments, and found the opposite?
 
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