Can someone identify the lume (if any) used on my vintage Bifora?

Thread: Can someone identify the lume (if any) used on my vintage Bifora?

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  1. #1
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    Can someone identify the lume (if any) used on my vintage Bifora?



    The hour markers seem to be made of the same material as the hands...except they are framed in the white box, which appears to be the same material that is on the center of the hands.

    The watch has zero luminescence at all so I may be totally wrong that it is lume. But can anyone recognize if this is Radium or Tritium or none of the above?

    Thanks!
    Last edited by Dudbear; September 22nd, 2014 at 05:19.

  2. #2
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    Re: Can someone identify the lume (if any) used on my vintage Bifora?

    I can't say for certain but I think it's just paint. If it is lume, it's only on the hands by the looks of it. The dead white colour (instead of very faded green or the like) is further evidence in favour of paint. A Geiger counter would put the issue beyond any doubt, of course.

    Hartmut Richter

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    Re: Can someone identify the lume (if any) used on my vintage Bifora?

    Quote Originally Posted by Hartmut Richter View Post
    I can't say for certain but I think it's just paint. If it is lume, it's only on the hands by the looks of it. The dead white colour (instead of very faded green or the like) is further evidence in favour of paint. A Geiger counter would put the issue beyond any doubt, of course.

    Hartmut Richter
    A Geiger counter would not pick up Tritium, a special "wipe test" is done with a liquid scintillation counter.
    Source: http://www.google.co.uk/url?sa=t&rct...75775273,d.bGQ

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    Re: Can someone identify the lume (if any) used on my vintage Bifora?

    Considering that the watch is at most 50 years old (more like 40), and considering that the half life of Tritium is ca. 11 years, you should still have ca. "1 divided by 2 to the power of 4", i.e. 1/16 or ca. 6.5% of the original radioactivity left. Not all that much - but still enough for a decent Geiger counter.

    Hartmut Richter

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    Re: Can someone identify the lume (if any) used on my vintage Bifora?

    Quote Originally Posted by Hartmut Richter View Post
    Considering that the watch is at most 50 years old (more like 40), and considering that the half life of Tritium is ca. 11 years, you should still have ca. "1 divided by 2 to the power of 4", i.e. 1/16 or ca. 6.5% of the original radioactivity left. Not all that much - but still enough for a decent Geiger counter.

    Hartmut Richter

    Quoted from the link above;
    DETECTION

    A tiny drop of contamination containing H-3 can be easily detected with a wipe test from a liquid scintillation counter. A Geiger counter will not detect the presence of H-3.

    Courtesy of Nukeworker.com.

    So as you can see, a Geiger counter does not work on tritium.
    Bob.
    Last edited by bobbee; September 22nd, 2014 at 23:12.

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    Re: Can someone identify the lume (if any) used on my vintage Bifora?

    I have a lot of vintage Tritium watches and they only have the most faint glow left but they all light up when you put them under a light source as the phosphor is still active. So if the dial is still dead after a light bath it's most likely not a Tritium watch and it also looks to modern for a radium watch.
    Last edited by Shum; September 22nd, 2014 at 23:35.

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    Re: Can someone identify the lume (if any) used on my vintage Bifora?

    I have a vintage Cortebert Turkish railroad w/w, and the hands and dial are almost identical. I know that the white on my watch's hands/dial are simply painted on.

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    Re: Can someone identify the lume (if any) used on my vintage Bifora?

    Many watch collectors use geiger counters to detect tritium; I'm not sure what that site you linked to is talking about. Tritium is pretty low energy though, so some types of geiger counters will have difficulty detecting it if they don't have a "wand" that allows you to minimize the distance between the tritium and the sensing unit. Or perhaps that site (which seems to cater to professionals who deal with radioactive materials in an industrial/commercial setting) is concerned about being able to detect tritium at dosages far below what you'd find on a watch dial.
    My growing collection of "affordable" vintages: http://www.abslomrob.com

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    Re: Can someone identify the lume (if any) used on my vintage Bifora?

    So this professional site is incorrect Rob?
    These "watch collectors" who use geiger counters to detect tritium in their watches, can you let me know if they have actually found any with their specially prepared Geiger counters?
    I can't see there being anywhere that uses such small amounts of tritium other than in a wrist watch, and as you say, these guys on that site are professionals in an industrial/commercial setting.

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    Re: Can someone identify the lume (if any) used on my vintage Bifora?

    Because in a industrial/commerical setting, the concern is very very small quantities of tritium that are in the air and water, as opposed to the comparatively high concentration of tritium required to generate luminescence. If you're trying to detect the presence of tritium in the air or in your tap water (a major concern in areas near nuclear reactors, for example) a geiger counter won't do it. Tritium is a very low energy beta producer, and it's radiation is stopped by nearly anything (like the crystal of the watch, a piece of paper or your skin). So geiger counters that use a metal/mica tube for detecting won't do it at all. However, other types of geiger counters have open window detectors that don't interfere with the beta rays (provided that the source is close enough to the detector), so for watch hobbyiest, they are a valid test. Here's a video demonstrating (admittedly, using a tritium source that's probably a couple of times stronger then your typical watch):
    https://www.youtube.com/watch?v=M-_4ijCPwTg
    My growing collection of "affordable" vintages: http://www.abslomrob.com

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