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DutchViolins

Bulbs for UV-chamber

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The website of this company shows a lot of components for varnishing an instrument with an oil varnish. What I’m interested in is the bulbs they recommend for making a UV-chamber. Here they refer to the Philips TL20W/03 RS. As far I could retrieve the radiation wavelength of these bulbs are 420 nm which is in the visible region of the light spectrum. In my opinion UV-radiation should be somewhere of 254 nm.

What is a good bulb for making a UV-chamber?

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The website of this company shows a lot of components for varnishing an instrument with an oil varnish. What I’m interested in is the bulbs they recommend for making a UV-chamber. Here they refer to the Philips TL20W/03 RS. As far I could retrieve the radiation wavelength of these bulbs are 420 nm which is in the visible region of the light spectrum. In my opinion UV-radiation should be somewhere of 254 nm.

What is a good bulb for making a UV-chamber?

The tubes mentioned in the article are standard "blacklight" tubes, which are perfect for drying oil varnish. The UV range of the EM spectrum is generally regarded as starting at around 400nm. No fluorescent tube emits at a single sharp wavelength: these blacklights will be emitting plenty of power in the near UV to dry your varnish and indeed tan the instrument. Going to the short UVC wavelengths you describe brings fairly severe health hazards for no benefit at all, at least when it comes to drying varnish.

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The tubes mentioned in the article are standard "blacklight" tubes, which are perfect for drying oil varnish. The UV range of the EM spectrum is generally regarded as starting at around 400nm. No fluorescent tube emits at a single sharp wavelength: these blacklights will be emitting plenty of power in the near UV to dry your varnish and indeed tan the instrument. Going to the short UVC wavelengths you describe brings fairly severe health hazards for no benefit at all, at least when it comes to drying varnish.

John, i found blacklights didnt work at all well for me.

Ive use the 3RS tubes and find them suitable for both tannning and drying varnish but it depends on your varnish.This site says the 10r ones are mainly used for photopolymerisation but i havent tried them.

3rs

10r

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If you check out Reptile lights on Google, or your local pet store, you'll find fluorescent lights with both high UVA, and UVB light output. Probably better than your standard blacklight bulbs, but also more expensive.

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If you check out Reptile lights on Google, or your local pet store, you'll find fluorescent lights with both high UVA, and UVB light output. Probably better than your standard blacklight bulbs, but also more expensive.

Hi Doug, tried reptile lights. No better than blacklights for me.

Bob, the 3RS tubes referred to by the original poster seem to be the ones that you are recommending so I don't think we are disagreeing? These are the ones that I use and my supplier calls them "blacklights".

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The shop i linked to in the above post ,also has blacklights with the blue `woods` glass.These are the ones i found pretty useless.

blacklight

I thought the function of the Wood's glass was just to filter out the visible range? I think the UV output is similar to the actinic tubes mentioned earlier.

But now Bob has mentioned it I agree that it's incorrect to describe the lights I/we use as "blacklights".

The actinic tubes specified in the OldWood documentation work fine.

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According to Wikipedia the Osram brand Wood's glass tubes use a fairly narrow-band emitting phosphor, europium activated strontium pyroborate with a peak at about 370 nm. Philips Wood's glass tubes use lead-activated calcium metasilicate that emits a wider band with a shorter wavelength peak at about 350 nm. Both are anyway below 420 nm!

Maybe there is no big difference between these types except for the price?

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This site shows a lot of options. Lamps online

I use blacklights at the moment ( blue glass ) - but I see here that the 'blacklight' flykiller tubes are in fact cheaper ( white glass - rated at 300 - 420 n )

Note that the 4' tubes in the woods glass are rated at 36w ( as are all the 'disco' type blue tubes ) - whereas the flykiller tubes are 40w - so I don't know if the ballast will handle that. Anyone know ?

Geoff

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I used F20T12BL lights in my box, and it seemed to work well, drying overnight. The guy at the specialty lamp store called them "350BL" bulbs, and that refers to the wavelength. Two of the four bulbs went weak lately, so I replaced them with Home Depot blacklights, F20T12BLB, as they are cheaper, and previous research indicated that the only difference is that the BLB has the filter that cuts out most of the visible spectrum. I expect that they should work the same.

I have not done any testing to see if either bulb functions better than anything else, I just know it's good enough for my puropses.

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Anything with a BL (BlackLight) or BLB (BlackLightBlue) designation should work fine for drying varnish. A reptile bulb was slower when I tried it, so was a tanning bulb, and so was a UVC (germicidal) bulb. I think the UVC was faster at tanning.

Ordinary bulbs leak enough UV to work too, but it takes at least twice as many of them to get a similar drying rate.

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The website of this company shows a lot of components for varnishing an instrument with an oil varnish. What I’m interested in is the bulbs they recommend for making a UV-chamber. Here they refer to the Philips TL20W/03 RS. As far I could retrieve the radiation wavelength of these bulbs are 420 nm which is in the visible region of the light spectrum. In my opinion UV-radiation should be somewhere of 254 nm.

What is a good bulb for making a UV-chamber?

I made my UV drying box out of tinfoil backed styrofoam insulation and two blacklight bulb/fixtures that I bought at Wal-mart for about $10 each. They are a light purple when turned on. I mounted the fixtures in diagonally opposite corners of the box. I didn't think that 2 would be enough, but they are. My box will tan a violin in 3 or 4 days and dry a coat of Hammerl oil varnish overnight (20 to 24 hours).

Bill

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Anybody try one of these rotating Christmas tree stands to turn their instrument in the UV box?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=300511407923#ht_897wt_1141

My bulbs are nearly equally spaced, and instruments dry fine without rotating. They dry slowest at the bottom, but rotating wouldn't help that.

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I hang the violin from the rotating mirror ball. Just loop a stiff wire loop/hook under the chin of the scroll. It leaves no discernible marks.

Some lamps are set low to catch the underside of the violin.

Mike

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I use just two of the Wal-Mart lights (lamps have been replaced once) in the back corners of the box. So turning helps and I use the motor from a surplus timer of some kind. It turns once about every 50 minutes, slow enough that it doesn't create a breeze B) . Also, one light is as high as possible and the other as low as possible. Most coats will dry in 10 to 12 hours and easily in a day.

Lyle

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