The Rot Doctor


Subject: Fuel Tank (and epoxy resin)
Date: Thu, 09 Mar 2000

I have a 40 year SS tank in my sailboat that I want to convert to the storage of Diesel fuel. The tanks have a lot of pin hole leaks at the welds and where they rested on the fiberglass hull. My thought is to encapsulate the tank in epoxy, using the SS steel as a base for cloth and epoxy adhesive after a thorough sandblasting. This is my alternative to building new tanks from epoxied plywood.?.?

I have used the CPES product extensively on this project and it is great. The flexibility is impressive. West System says that their product will work in a diesel tank application as I have described However I am concerned that their product is extremely rigid , inflexible etc. in comparison to the CPES product.

Do you have an epoxy system that is compatible with the CPES and offers the ability to expand and contract with the SS core, as well as being compatible with the Diesel fuel environment??

Any help would be appreciated.

I checked with our tech people and they confirm that there is no incompatibility between cured epoxy and diesel fuel. The key is abrading the surface enough to give the resin something to grip -- hence the sandblasting recommendation.

The West epoxy (as well as other petroleum-derived resins) hardens to a very rigid surface. By itself, cured in a thin layer, it will shatter. The cloth, of course, helps prevent this. Our Layup & Laminating Resin retains a slight degree of flexibility and will bend before it breaks -- and it breaks, not shatters. It is somewhat more expensive than West, but then you are getting (in our opinion) a superior product. It also has a much slower cure time than the standard epoxy resins, mixes 1:1, and leaves no amine blush.

The application of CPES to any areas with pin holes would definitely be very beneficial. In fact, I would recommend applying two coats to pin hole areas before the application of a heavier resin/cloth. Allow a day between CPES applications. Following that, apply the cloth/L&L Resin, which will bond quite securely to the CPES-treated seams.

Come back if you have additional questions.