Epoxy Barrier coat

[stevemorrell]

I am looking into purchasing a 1981 Ericson 38 which apparently (and confirmed on inspection) has no blisters because of a previous gel coat job where it was removed and replaced with an epoxy layer but never given an epoxy barrier coat like Interprotect 2000E/20001E. It has bottom paint directly on the epoxy. I believe this needs to be applied as soon as possible, but the antifouling was just put on new. Does anyone out there have an opinion on this? Should the new antifouling be immediately removed and the barrier coat applied or should one wait a year till the bottom paint needs to be redone and do it then? How urgent do people believe this is? The epoxy job was done about three years ago.

Steve Morrell

[paulk]

What is Interprotect but an epoxy layer? It sounds like whatever epoxy was put on your hull simply doesn''t have a fancy marketing name. Despite fancy names and advertising, epoxy (like gasoline) is epoxy. If you''ve got a layer of it, it doesn''t matter who made it. If there aren''t any blisters now in a 1981 boat, it sounds like you''re trying to fix a problem you don''t have. Get some new sails instead, you''ll have more fun.

[stevemorrell]

Maybe I did not leave enough information there. The boat did have blisters several years ago and the boat was dried out and the original gel coat removed, then an epoxy "resin" coat was put on to replace the gel coat. This is like Interprotect 1000/1001 or Epiglass HT 9000 resin as recommended by Interlux. Then, as reccomended by Interlux, an epoxy paint is applied. This boat never had the epoxy paint applied, but did have the epoxy resin.

[Jeff_H]

Putting an epoxy barrier coat over a properly applied epoxy laminate is like wrapping a plastic bag in a waxed paper bag. Depending on whose products were used and how they were applied, there are few plastic materials that are more water impermeable than epoxy resin. Un-thickened epoxies (like WEST System, MAS and System 3) work best with final overcoats of their own epoxy resin.

Putting another product over this layer is un-necessary and frankly potentially less successful.

In my opinion the only reason that the epoxy paint (which has pigments and solvents and therefore is more permeable than the resin) is added is to provide a "marker" coat so you don''t actually sand down into the epoxy resin coats. Also, Epoxy does not stand up to UV very well and so the epoxy paint coat acts as a sunshield to protect the epoxy resin should there be a time when the boat is out of the water and the raw resin is exposed.

I do question the replacement of only the gelcoat as a proper repair method. Rarely is the problem only in the gelcoat. Usually the problem is actually in the laminate below the Gelcoat. Merely replacing the gelcoat with a an unreinforced resin (or barrier coat) layer rarely solves the problem. Most qualified repair people that I have talked to seem to suggest at least a single layer of epoxy reinforced with glass cloth as a proper cure. The gelcoat layer is too thin to provide a thick enough and strong enough repair to be a permanent solution. A paint on barrier won''t change that.

Respectfully

Jeff