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Jerryc41
08-30-2017, 11:15 PM
I'm making a cigar box uke, and I thought I'd cut rosewood veneer for the head. Since I'm spraying the neck and body with polyurethane, I thought I'd spray the rosewood veneer on the head, too.

Slight problem. It's not shiny, and it's staying sticky. Is there a problem spraying polyurethane on rosewood, or does it just take a very long time to dry?

jcalkin
08-31-2017, 03:51 AM
I've had trusty finishes, including poly, react strangely with a particular piece of wood and refuse to dry as normal. Given enough time they always dried, but if you don't want to wait remove it now while its tacky, let it dry, rub on a quick coat of shellac and try the poly again.

Allen
08-31-2017, 05:45 PM
Many of the Rosewood family of timbers act like an anti-catalyst to some finishes. If it's drying fine on the neck then I suspect this is the problem. In that case you must isolate the timber with a sealer, or pick another finish.

sequoia
08-31-2017, 06:55 PM
I've never had that problem because I've never used polyurethane on rosewood, but my first thought would be that those nasty rosewood oils are reacting with the polymers and or dryers. Could be. But in these sorts of situations the nice thing about the peghead veneer is that you can just sand back to bare wood and start over again. If you do that, (easy), wipe the rosewood with a solvent like methanol (whatever) and keep wiping until the cloth stops staining red and then quickly (the oils underneath will migrate to the surface surprising quickly) apply your sealer.. Rosewood is a strange oily wood. But so beautiful. I love it. I hate the oils though. Nasty.

Titchtheclown
08-31-2017, 08:01 PM
Uv light will fix it. Here in Australia we use a large yellow source of UV and other wavelengths of light we mounted in the sky for this and other purposes. We like to call it the sun. It can cause bubbles with out gassing but it is cheaper than a UV light setup.