Rickresource Rickenbacker Forum

So if I am understanding this correctly, Todd says that UV inhibitors are essentially anti-oxidants and are eventually consumed. Paul says that they act like a pair of sunglasses and block (filter?) the UV.

Ted, my point was that there are different way to inhibit UV.

I really like that aged MG finish look. A 68 4000 for sale a year or so ago was now a deep amber due to age and exposure and looked stunning IMO.....

Are most UV inhibitors consumed as they work?

"Most". That's a Bill Clinton question.

Granted, my background is wooden and/or wood/composite boatbuilding, but if we're talking about U.V. blockers in resins and varnishes, they're often something like transparent iron-oxide pigments that let visible light through, but which block UV light which have been mixed into the medium. There is a limit to how much you can add and maintain a nice clear finish (and how much you can afford to add as they aren't cheap). This leads me to believe that there are likely tiny spaces between the blocker particles that will still allow some UV in and eventually degrade the finish. We used to use one called "U.V.9" (always thought it would be a good name for a band) which was a yellow powder that we mixed into epoxy and polyester resins (maybe one teaspoon per gallon of resin). Even so, the best form of protection for epoxy clearcoats on boats is still a heavy initial application of high-quality U.V. filtered varnish on top of it and fairly frequent varnish re-application to renew the protection. Since the epoxy resin base coats will only stand about 250-300 hours of sunlight before they start to deteriorate, it's a big deal on boats. Since most Ric owners don't stand out in the yard all summer with their guitars, it would obviously be less of a problem, but I'm still not keen on the idea of purposely sun-tanning your Rickenbackers. This is my version of Autumnglo....

I don't know if this applies but I used to work in the petroleum industry (Tenneco). An oil additive that performs that function would be called an anti-oxidant. I don't remember them being particularly expensive but they are normally used in small quantities as you mentioned. Are UV inhibitors anti-oxidants or is the mechanism entirely different?

Let me get this clear, Todd...you varnish over epoxy resin? Standard alkyd or urethane (one-component) varnish?

I would think that this would be a big no-no. I think the reason for re-varnishing is due to the varnish chalking and flaking, which these one-component varnishes do.

UV inhibitors are to anti-oxidants as pears are to telephones.

So, what is the mechanism then?

I don't know a darn thing about this stuff, but I'm sure glad you guys do! Thank you for sharing this discussion with the forum. Insteresting stuff.

Yes Paul, you absolutely have to varnish over epoxy clearcoats for boatbuilding. Otherwise, within a year or less the resin turns yellow, gets rubbery and you can scrape it off with your fingernail. It's standard practice with any brand of boatbuilding epoxy and about the first thing the resin makers will specify in their instructions for clearcoating. Most people use high-end, one part marine varnishes specifically made with lot of U.V. filter in them. Some use two-part linear polyurethane varnish, but it's pretty toxic (cyanide). You can't spray it unless you wear a space-suit and have piped-in air. If the manufacturer also makes a brushing hardener you can brush it, or on big areas you roll it on with a thin foam roller and immediately tip-out the bubbles with very light strokes using just the tip of a soft paint brush. Even the few resin formulas which contain some U.V. filtering stuff will come with a warning that it's only a helper and not sufficient protection all by itself. So after the resin is applied, you sand it smooth and then add 2-6 coats of varnish, scuff sanding or leveling where needed between coats.

This is an old boat that I rebuilt. It had cedar sides which were constantly checking and cracking the paint topcoat. I sanded off the paint, then laminated 3/32" mahogany over the sides using epoxy resin. Then I sanded the surface smooth, stained it with alcohol-based, analine dye stain, rolled and tipped six thin coats of clear epoxy resin over the that, sanded it smooth again (using a big disk grinder and a feathering disk to about 220 grit) and then applied about five coats of varnish on top to protect the epoxy. Varnishing was done with a roller in one hand and a brush in the other. I'd start at one end and work my way all around the hull. I ended up with some really lovely flamed mahogany.



The only other ways to protect epoxy from U.V. on boats are to paint over it with opaque paint, covering up the resin, or to mix in about 10% worth of graphite powder. This stops the U.V. from penetrating by essentially sacrificing the very top part of the layer, which works as a blocker. A lot of "graphite" products (graphite-filled resin, not graphite as in carbon fiber) are made this way. These usually have a satin black/dark grey finish. Graphite fishing reels are an example. The graphite fishing rods (and also other products, like golf club shafts and ski poles) contain clear resin and strands of carbon fiber, but the fishing reels are basically just a mixture of some sort of resin and graphite powder to block U.V.

One thing we must remember: All wood surfaces build up a very thin layer called patina. Maple shows this the most since it's a white wood. This is caused by U.V. and age. Most all finishes that turn yellow or amber as I like to refer to it, will still have a patina to the top layer of wood. Most of us like that look while others drive Chevy's.

Ahh-
That's why my Jaguar's dash looks better and better

When I redid the dash and window caps on my Silver Shadow, I clearcoated them in conversion varnish. Five years later, they were still as good as new.

I'm not a boatbuilder, but I couldn't imagine varnishing over epoxy resin. It's like painting lacquer on glass--guaranteed adhesion failure and a recipe for constant upkeep. And I certainly would not recommend this for guitars, in case anyone is thinking of it. It's a method peculiar to boatbuilding and restoring.

Following the experiments with my Silver Shadow, my woodie car was redone in CV in 2002. Since then, frequent and regular doses of tropical sun have done nothing that I can tell to compromise the finish in any way. It still looks mirror-glossy now. This is 300 miles south of the equator! 15 minutes in the sun at noon would turn me into a Lobster Replica.

This was after years of listening to the woodie guys talking on and on about which brand of spar varnish and the Brotherhood Of Sanding Your Butt Off Every Three Years Or So, just to apply a fresh coat of spar or four, sanding between those coats, too.

I sprayed four wet coats of two-component CV, sanding between those, and the result is quite stunning and apparently a heck of a lot more durable than ordinary air-dry varnish.

Todd, that boat looks terrific and you certainly know your boatbuilding and finishing stuff!

And, Dale--I prefer "amber" to "yellow" as a choice of words, too...

While we're on the topic of yellowing, what would be the best way to take the yellowing off a Tuxedo? I much rather have it all bright white, is there a way to restore the original factory color without getting too nasty like a refin? Although I may change my mind once it finally arrives.