Fiberglass and mineral spirits?

[Michael K.]

I am replacing the fuel tank in my 57 and I wanted to clean the unpainted fiberglass in the tank area. I scraped all of the heavy dirt and grease accumulation off. Can I use mineral spirits on the unpainted fiberglass? Will it cause any future problems?

[Richard F.]

Re:Fiberglass and mineral spirits?

Acetone. Dampen a clean rag and wipe unpainted/bare area. Residue evaporates quickly.

[Duke W.]

Re:Fiberglass and mineral spirits?

Acetone is a very strong organic solvent. It will not harm cured fiberglass - at least if use sparingly, but it will dissolve any paint while not being a very good solvent for oil and grease.

Mineral spirits in a spray bottle along with an asortment of brushes like old paint brushes is the best way to clean areas contaminated with petroleum product residues, and it is inexpensive.

Save the lacquer thinner and acetone to use sparingly as the last resort for materials that mineral spirits won't remove.

Duke

[Chuck S.]

Re:Fiberglass and mineral spirits?

Duke, if the area is to be painted, I prefer to use lacquer thinner rather than acetone or mineral spirits. If the area is to be left in bare glass, it probably doesn't matter if mineral spirits is used.

Acetone is aggressive on polyester resin, and if left there very long it will make the surface sticky, meaning it has dissolved some of the resin. Mineral spirits is petroleum based and fairly "oily" in my opinion. If the area was to be painted later, I would be concerned about it leaving an oily residue. It does evaporate, but slowly.

Polyester resin will also be damaged by lacquer thinner if exposure is continuous for some time (requires frequent application to keep surface wet). It is, however, an excellent degreaser and a very effective solvent on paint overspray. It vaporizes quickly leaving no product residue, and typically without effecting the resin.

[Duke W.]

Re:Fiberglass and mineral spirits?

I know kerosene or diesel fuel leaves an oily film, and I never use it. In my experience mineral spirits dries fairly rapidly and doesn't leave behind a film. Likewise my experience with lacquer thinner is that it doensn't dissolve and wash away petroleum product residue as well as mineral spirits.

I would never soak a fiberglass part in any kind of solvent bath, but spraying and wiping with mineral spirits or just spraying and letting it drain off a vertical surface should do no harm.

Duke