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Bultaco Fiberglass refinishing


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Hello all, new to the forum here.  I raced Pursangs as a teen in the late 70s, and I’ve recently purchased a Bultaco project.

The bike has never been repainted, and the color is molded into the gelcoat on the tank.  The tank has many stress cracks in the gelcoat.  I plan to coat the inside of the tank with one of the tank sealing products on the market.  For the outside of the tank, I’d like to just clearcoat over the original gelcoat to protect it and seal the cracks somewhat.  Has anyone done this?  What do you Bul experts recommend?

Edited by 70sBulRacer
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Originally Bultaco tanks had no sealer of any description from the factory and they never had an issue. The problem today is ethanol in the fuel, as it really attacks fiberglass. Caswell seems to be the most widely used by all of my friends. My tanks are all sealed with  a cup full of colored resin and I've had no issues but I don't use ethanol based fuels. Regarding the stress cracks in the original gelcoat I think that's a much bigger issue and can't see a clear gelcoat solving the issues, I would be more inclined to sand al the stress cracks out and apply another original colored gelcoat. Non of this is really expensive just time consuming

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