drying varnish/ french polish

[rwh4]

Does anybody use ultraviolet light to dry varnish?I'm looking for a way to speed the drying time.I'm french polishing over the varnish and the surface is still very delicate after three weeks of drying time.I'm assuming you build an enclosed box with the UV lights inside and place the instrument inside.How long do you leave it in,what wattage bulbs and how many.Do you dry only the varnish coat or can you also dry the french polish?
Any good web pages out there?

[HoGo]

Check out the violin forums out there. Most violin makers use UV drying-boxes. I personally use Philips UV unit for suntanning face- there are 4 tubes which do not produce almost any heat (10watt each). I usually use this only on tops to prevent bridge damage to the OIL varnish. But I plan to disassemble and place the tubes into four corners of some box lined with aluminium foil to dry whole instruments in the winter. You can buy used, as I did, for a very low price or you can you can buy the tubes and make the rest yourself. Just be sure they do not produce much heat (IR).
And I forgot to say that it makes my varnish dry to touch in less than two hours and 6hrs is enough to apply next coat. After last coat I give the top another 8-10hrs. Maybe there's problem with drying properties of your varnish, too. What do you use? Do you add dryers to the varnish?

[Scotti Adams]

..My Builder..Ben Wilcox uses such a devise....built it himself...seems to do the trick..

[HoGo]

And Gibson is using it, too.

[Big Joe]

We have our own UV booth. I really cannot discuss it very much but to say it takes a certain spectrum of the UV to do any good. That particular spectrum is very harmful to the retinas so you must not have the lights on when looking at them. You have to have a safety to shut the lights off before you see in your booth. I believe it is the "B" spectrum. Anyway, we have been using one for a long time and it really works but it is not something to take lightly.

[Chris Baird]

I use uv as well and it makes a big difference in drying time. I have, in fact, left the lights on too long and the finish got very hard and made for some difficult level sanding. I like to have the finish under the lights for about 12 hours between coats. That gets the finish dry enough but not too dry.

[rwh4]

I'm using The Z spar boat varnish that Lynn Dudenbostel recommends.I assume varnish is varnish and the UV will have the same effect on whatever varnish you use.Thanks for the good info.I will look into the violin group.

[sunburst]

I don't know how it will affect the process, but one of the things that makes spar varnish spar varnish is a heavy dose of UV blocker. It's formulated for exterior marine use and needs to resist sunlight. For that reason it has a lot of plastisizer as well as a lot of UV blocker. The plasticizer is probably good for preventing weather checks, but the UV blocker might mean it resists UV curing.(?)

[HoGo]

I believe the Z-spar as well as most commercial varnishes do not need UV to dry properly. The UV blocker is present in most outdoor varnishes and lacquers to prevent deteriorating of the coating in the strong sun.
My tubes are UV-A and work fine. The sunlight contains UV-A, UV-B and UV-C light. The A is the weakest but most penetrating and the C is strong and has little penetrating power. I like the A as it will dry the varnish layer evenly. The C may cause the outer surface to dry much faster than the varnish under and make the layer varnish craze.
The B could be the best compromise.

[Gavin Baird]

To clarify the subject: are you people talking about Spirit Varnish or Oil based Varnish or are you referring to both?..G

[Chris Baird]

Oil varnish. UV doesn't seem to do much for shellac.

[Big Joe]

oil varnish. Actually, from what I understand, it is not the UV as much as the ozone it causes that makes the finish dry faster and harden properly. We can use it with french polish and with some spirit varnishes in repairing mandolins with spirit varnish. The real value is the oil varnish though.

[Yonkle]

I just re-finished my #2 mandolin. Took it from lacquer, to shellac using the French Polish Techinque. Anyway I got it all rubbed out nice and shiny now and it has been in my closet about 5 days. I used only shellac flakes (blond) and alcohol for this finish.
Question: How long should I let the new finish dry before stringing her up?? I don't want the bridge to dig into the finish. It's been done for 5 days, but I am not sure if this is long enough, I want the hear it and play it, but I don't want to jump the gun and ruin the finish with the bridge. What is a good safe time frame?? Thanks JD

[Chris Baird]

You can't stop the bridge from digging in. But, I usually like to wait 2 weeks before stringing up after french polishing. Shellac will eventually get pretty hard but to start out with it scratches very easily. Just the calouses on my left hand are enough to put lots of scratches in new shellac.