Official Luthiers Forum!

Those of us that use epoxy for pore filling might find this article enlightening:
http://www.oneoceankayaks.com/Epoxtest.htm

Although instruments aren't generally left out in the elements, UV comes from many sources, and over the long term might effect the clarity of the epoxy under a (non UV protecting) finish. Depending on the epoxy used and the amount left on the surface it may be more or less of a concern.

Great write up about the epoxys.

I wonder how the epoxy holds up under UV relative to nitro or some of the other finishes. My question would be how have the top coats held up before the UV exposure really affects the thin layer of epoxy left on the guitar from the pore fill. I have four fiberglass kayaks and they get hundreds more UV exposure than my guitars.

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http://www.Harvestmoonguitars.com

The resin used in commercially built boat hulls (and perhaps your kayaks) is generally polyester, which does better with UV than epoxy. I believe the test was aimed at those who home build kayaks and canoes from wood and coat them with a layer of glass and epoxy. They then usually protect that with a UV blocking varnish.
Other finishes are not immune to fading, cracking, clouding and chalking. Even polyester over the long run will fail. I have some wood panels in the cab of my truck that the polyester has cracked, become cloudy, and flaked off. French polish - one of the thinnest and most delicate of the finishes may also be one of the longest lasting and most easily renewable.

"Epoxy" covers a range of thousands of products. The only guarantee that an epoxy product will have ANY UV protection will be when the manufacturer TELLS you it has UV inhibitors as part of the formulation.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Hi Stuart,
You seem to be a person who knows a lot about epoxies, so I would like to "pick your brain" a bit. West Systems puts UV inhibitors in its 207 hardener. Is that how it is usually done? Another question - I had some older 207 hardener that had turned very dark, but after mixing with resin was amber and the mix cured fine. Would it still have the UV inhibitor qualities?
3rd question - can something be added to epoxy by the user to give it UV inhibiting qualities. Although it may be less of a concern for guitar building, I also use epoxies for out door items and would like to know more about it.