Red Stain

[Stophel]

Well, a UV lamp is out of the question!!! :nono: First of all, the "Germicidal" and "curing" lamps are very powerful and emit UV-C (short wavelength range), which is VERY dangerous!!! (not to mention that they are quite expensive...). I have found that SOME sun lamps (tanning lamps) will emit UV-B light (medium wavelength range), and the common black light is UV-A (long wavelength range). Greywolf, will a black light be sufficient? Have you tried it?

I thought of "full spectrum" bulbs too, but getting any COMPLETE information on any particular bulb is difficult at best, so it's hard to say how much (if ANY) UV light is present. My guess would be that if there were any, most of them would not even be as powerful as the black light.

I'm going to dig up a black light and give it a try and see if it works.

There are also "rock hunting" lights, which, as I understand it, are somewhere between the black UV-A and UV-B...Not sure about this yet though, I'll keep looking.

 

Chris - frankly I haven't had to use a UV lamp for curing since we moved here to SW Colorado. Doing a quick search of commercial units they all seem to use UV-A, so break out that black light and give it a try. IIRC metal halide lamps are also pretty high emitters of UV.
Partly I remembered about using UV after reading some of the violin maker sites.
BTW - I've been experimenting using alum as a dryer. Alum shows up as an ingredient in several of the old varnish recipes as well as in spectroscopic analyses of old violins. Nothing definite yet but so far the results are encouraging. Also have been thinking about starting with some of the artist grade linseed stand oils, they sure sound like a short cut since from the info garnered those stand oils are heat polymerized linseed oil, so the "cooking" time should be much less.

 

[Stophel]

I put a scrap piece of wood with varnish on it with two 18" blacklights right in front of it. It sat for about 20 hours overnight before I looked at it again (in an otherwise unlit shop building). When I looked at it last, it was about 2/3 dry...obviously not nearly as effective as 5 hours in the sun, but I don't have any sun now.

The same piece of wood with the varnish on it could have sat in the shop for months without even beginning to dry.

The little 15w bulbs are not exactly "intense" (though it is unpleasant for me to be looking in their direction)...now if I had two 40w 4' bulbs to put in the shop light....Hoowah!

 

[benvenuto]

Halogen bulbs are high UV-B emitters - not a problem 6 feet away in the ceiling but up close...

Halogen desklamps were banned at my workplace after reports of facial skin cancers in office workers linked to the lamps. It appears several people removed the "ugly" safety filter from the lamps

 

[Stophel]

Well, I came home early today to take advantage of the sun (though it is only 35 degrees) and set my stock out to finish drying.

I made a crude reflector out of a couple of boards nailed together in an angle so it would stand up on its own and laid some aluminum foil over it to act as a reflector for my two black lights. I stacked them on top of one another to get as much length of the stock in the light as I could. It DOES work, though very slowly. It's not as good as having the stock in the sun, but if there's no sun, it certainly is better than nothing!!! :winking: