100% silicon question

[Michael Weber]

Trying to McGyver a temporary closure for my 3 gallon auxiliary fuel cell. The original is somewhere along the highway in South Dakota. Anyone know if cured silicon is impervious to gasoline?

[Lee Schierer]

In my experience silicone sealant is not resistant to gasoline.

[Edward Dyas]

I don't think anything is gasoline proof. I think the most resistant is Permatex 85420. It's a polyester urethane sealant.

[Michael Weber]

Thanks, using a different sealing method.

[Bill Dufour]

Not recommended and any sealent is not pure silicone so even less resistant.
Urethane is good but again any sealer is not pure.

Bill D
https://www.engineeringtoolbox.com/silicone-chemical-resistance-d_1879.html

I could not show a link to warco which has a better table.

[Dave Anderson NH]

Silicone (Poly methyl siloxane) is attacked by gasoline and swells as much as 100%. As soon as the gas evaporates and is gone from the molecular structure it will return to the original size. For resistance to gasoline and petroleum based products you need flourosilicone. It is far more expensive than silicone and is much harder to find in an RTV.

[Mark Major]

polyprotech gas tank adhesive will work; can't recommend a source in the U.S. though



Mark