Topic: Tank Sealing Woes

[chimmychong86]

After a bunch of work done to my bike I finally sealed the original 70s Dunstall tank with a caswell kit and everything seamed to be going well untill the paint started blistering on the bottom left of the tank. Now since i know the integrity is gone inside the sealer i'm debating cutting the top off the tank peeling all the liner off and starting a new. Has anyone ever taken one of these tanks apart and put it back together? Any kind of documentation of what the insides look like? It seemed to like it had separate compartments in there when I was looking around with a flashlight.  Any help/advice is greatly appreciated.

[xsmooth69x]

lots of paint thinner gel then rinse out with mineral sprite and start over?

[chimmychong86]

wouldn't doing that just ruin the integrity of the glass more?

[Rookster]

Yes.  That is a poly resin tank which will be weakened/dissolved by ethanol.  Your options are to use only non ethanol gas or try to re-seal.  I think Caswell does not recommend their sealer for fiberglass tanks.  I have used KBS and Hirsch sealers on fiberglass tanks.  I had trouble with the KBS.  I think the KBS is more of a paint than an actual sealer.  The Hirsch has worked better but it is not perfect either.  The bottom line is poly resin fiberglass tanks are no longer useful as motorcycle gas tanks.  Any sealer that you put in there will fail at some point.  Think of it this way: line a styrofoam cup with any of the sealers and then pour gas into it.  How long will it last before the gas gets to the styrofoam and melts it.  Now imagine heating and cooling the cup over and over again then shaking it up.  Even the new Dunstall tanks don't hold up well to modern gas.

You could try to line it again and see how far you get with it.  Some people have very little trouble.  I have had a bunch of trouble with my fiberglass tank and it was made 2 years ago!  The only reason I recommend Hirsch is because you can recoat it without having to get all the old sealer out.  I plan on recoating my tank with Hirsch over the winter and probably every winter after that as part of my maintenance schedule.  And Hirsch does recommend their selaer for fiberglass.

Scott

[xsmooth69x]

oppps ya dont do what i posted i didnt know you had a fiberglass tank!!

[chimmychong86]

how would you all recommend getting the remnants of the current liner out?

[chimmychong86]

sorry to bump my own question, but I'd really like to know if there is a safe way of removing a liner out of a fiberglass tank, or if i should just reline the whole thing with the current stuff still there?

[Rookster]

If the liner has failed, regular gas and drywall screws should loosen it up and scrape most of it off.  That takes time though becuase you have to let the gas really soak that liner and start it peeling.  Your probably looking at several applications of gas, screws and shaking.  If you want if off in a hurry use MEK or acetone instead of gas.  Be careful though both will soften the poly resin that your tank is made of.  If you do it quickly several times and let the tank dry out in between you should be ok.  I wouldn't fill the thing up with MEK or acetone and let it sit or you will have a really soft tank.

If you get most of it off then the new liner should cover whatever is left.  This is why I like Hirsch sealer becuase you can recoat as many times as you want without removing it.

Scott