Uv Protected Finishes

[low end fuzz]

is there a finish that will keep paduak and purp/heart from going brown if left in the dark?

[Drak]

It's sunlight that makes them change color in the first place, keeping them in the dark (preferrably in their case) is the best protective measure you can take.

I've seen this question before, there's really no good answer that will overcome Mother Nature, as they say 'it is what it is'.

[leeranya]

before you varnish it all wipe some sunscreen with a high SPF value

just kidding

"The first step to prevent weathering is to block the sunlight. Finishes differ in their ability to protect wood from the sun. Paints can block sunlight completely, but they can trap moisture and encourage decay. Semitransparent stains are the next best way to block sunlight, followed by water-repellent preservatives, especially those that contain ultraviolet (UV) light inhibitors."

googled, taken from http://www.toolbase.org/Building-Systems/L...xposed-outdoors

Edited November 7, 2006 by leeranya

[rbjem]

Most automotive polyurethanes contain UV protectants. If you go that route you should be fine. Nitro on the other hand, I'm not too sure about that.

[Southpa]

Acrylic lacquer has better protection than nitro, thats one of the reasons why the big companies switched over to acrylic in the 60's. If you want the ultimate in UV protection then look for products used in the boat building industry. I've used spar urethane clear sold by Minwax ala rattlecan. Its used to protect naturally finished woods on yachts etc. from the effects of UV, not to mention providing an extremely hard, salt resistant coating.

Edited November 8, 2006 by Southpa

[al heeley]

He's right you know. UV causes nitorcellulose to cross-link which causes shrinkage and brittleness, as well as yellowing. Acrylic and poluester are a lot more chemically inert to UV damage. Some of the best are the polyurethane/acrylic hybrid resin blends, they get very hard, very resistant to chemiclas, water and uv, and remain very inert with age.

[Southpa]

Some of the best are the polyurethane/acrylic hybrid resin blends, they get very hard, very resistant to chemiclas, water and uv, and remain very inert with age.

Yep, thats the ultimate in finishes. Unfortunately, polyurethane resin paint is VERY expensive and VERY dangerous to handle. Thats the stuff thats loaded with proven cancer causing isocyanates. You basically need to wear SCUBA while shooting that stuff.

[mpeg2]

I'm getting pretty good results using Spar Varnish. Not the easiest finish to apply (meant for brushing) - but it's designed for marine uses (sitting in direct sun all day) and has pretty good UV protection. I've used it on Padauk with good results.

RIch