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  1. #11

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    I don't know the reason why she would want to go to regular tubes for larger than 8X10. It seems to me that a larger unit built with the spiral tubes should be just as effective as a small one, at least in terms of weight and cost.

    However, if I were to build a unit with the spiral tubes I would probably plan to space them closer than on 6" center. The more radiation you get over a given area the faster your printing times, and I calculate that if you were to space at 3.5" on center the unit would be more effective than one built with regular tubes.


    Sandy

    Quote Originally Posted by Shinnya
    Sandy,

    Thank you for posting Judy's message. I have one question:

    What would be the reason why she would use tubes when she moves to anything larger than 8x10?

    I am trying to build a larger one than currently I have (22x24" with 14 tubes) in order to accommodate many frames at the same time. My thought was that it would be cost effective, easier to build (less materials), and lighter.

    As for other details, a use of 20w bulbs and 6" OC seem to work fine...

    Any thought on this? Thank you for your time.

    Warmly,
    Tsuyoshi

  2. #12

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    Probably the only advantage of the spiral bulbs would be a higher energy density as Sandy suggested. One bad thing about the spiral bulbs is the ballast will be in your box. With normal bulbs you can put the ballast somewhere else so there will be less heat.

  3. #13

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    I am not sure how these spiral tubes work, but there does not appear to be any ballast as they screw directly into regular household sockets. And so far as I can see they do not seem to produce more heat than tubes, though I would certainly recommend the use of a fan with both the spiral and regular tubes.

    Sandy


    Quote Originally Posted by avandesande
    Probably the only advantage of the spiral bulbs would be a higher energy density as Sandy suggested. One bad thing about the spiral bulbs is the ballast will be in your box. With normal bulbs you can put the ballast somewhere else so there will be less heat.

  4. #14

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    The ballast is in the socket. It doesn't use a coil but some sort of thyrisistor to limit the current. I have seen this on little HPS units. They do make heat though.

  5. #15
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    I believe the electronic ballast is in the base of each bulb. This base does get warm, but, in my experience, not hot. I believe a large muffin fan would keep a bank of these cool enough to prevent adversely effecting exposure times.
    Jim

  6. #16

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    It probably isn't an issue then if you need to use fans in either case.

  7. #17

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    So y'all are using compact black light florescents to make a light table? Interesting. I tried black light--incandescent & florescent bulbs & tubes--to print gum. Nothing gave me any exposure. I finally bought an old GE sunlamp. Works great. (The instructor of the class had offhandedly dismissed it when I'd suggested one.) I just tip a fan toward the surface of the contact printing frame while the exposure is underway and for cool-off afterwards. Of course it's a hit-or-miss propisition finding one, but I've since bought a new old stock replacement bulb too.

  8. #18

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    The incandescent Black Light bulbs put out very little if any UV radiation so they are essentially useless for UV sensitive processes. The spiral BLB tubes, on the other hand, appear to put out as much UV radiation as a regular tube of the same wattage. Not sure why you were not able to print gum with BLB tubes as this process is highly sensitve to UV radation at about 350 nm, which is where BL and BLB tubes peak.

    Sandy


    Quote Originally Posted by Poptart
    So y'all are using compact black light florescents to make a light table? Interesting. I tried black light--incandescent & florescent bulbs & tubes--to print gum. Nothing gave me any exposure. I finally bought an old GE sunlamp. Works great. (The instructor of the class had offhandedly dismissed it when I'd suggested one.) I just tip a fan toward the surface of the contact printing frame while the exposure is underway and for cool-off afterwards. Of course it's a hit-or-miss propisition finding one, but I've since bought a new old stock replacement bulb too.

  9. #19

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    I've heard that most alt printers today use the sodium-vapor lamps you can buy at hardware stores. I haven't tried one--that was next on the list if the sunlamp didn't work.

  10. #20

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    That is news to me. I don't know of anyone using a sodium vapor lamp for printing with alternative processes.

    Anyone here have experience using one?

    Sandy




    Quote Originally Posted by Poptart
    I've heard that most alt printers today use the sodium-vapor lamps you can buy at hardware stores. I haven't tried one--that was next on the list if the sunlamp didn't work.
    Last edited by sanking; 12-21-2005 at 11:41 AM. Click to view previous post history.

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