A Reliable Temp Gage

Discussion in 'Darkroom Equipment' started by Richard Jepsen, Dec 23, 2009.

  1. Richard Jepsen

    Richard Jepsen Member

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    I held on to my 37 year old Weston dial temp gage even as the correct temperature drifted to - 2 degrees. Yesterday I dropped the gage and it now reads +3 degrees in error. I had no idea a jar could displace the temp so much but it did. :surprised:

    Its a hassle to double check the older Weston's accuracy and my confidence in its consistency is low.

    Can anyone recommend a reliable temp gage considered a best buy or can one re-calibrate the old Weston temp gage.
     
  2. John Koehrer

    John Koehrer Subscriber

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    If it's got the nut behind the dial it can be adjusted. Just loosen it & twist the dial.
    Inexpensive digital thermometers are available too.
     
  3. nawagi

    nawagi Member

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    Get a large styrofoam cup and fill it with crushed ice. Add cold water and allow to sit for 5 minutes. Loosen the lock nut on the back of the dial and submerge the shaft in the ice water. Allow to sit for 60 seconds, then twist the dial face so the needle alligns with 32 degrees F/ 0 degrees C. Tight the lock nut. You thermometer is now calibrated.

    If you have access to lab thermometers (mercury-filled) you can perform the procedure at different temperatures- preferably at your preferred developing temperature.

    Watch out for the electronic digital thermometers- my experience with the three or four I've tried shows that they are not that accuarate (plus or minus 3 degrees to a calibrated lab thermometer) and worse, they tend to 'wander', giving slightly different readings of the same temperature fluid over mutiple measurements.

    Those Weston's are the bomb. I have one thats about the same age and has carried me from the self-made "closet" darkroom to the halls of MoMA- and it still waits for me by the darkroom door with its leash in its mouth when I show up with a bag of plates.

    NWG
     
  4. Richard Jepsen

    Richard Jepsen Member

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    Crap, no nut on the back. Maybe I should keep this old friend & continue to cross check the equivalent temperature reading with the actual temp. As long as the Weston is consistently wrong, there is not much difference in how I used it the last 37 years. Just a different math calculation to use adjusting to the correct temp.
     
  5. chriscrawfordphoto

    chriscrawfordphoto Member

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    The Kodak Process Thermometer III is the only really accurate one. Its a mercury thermometer, so you have to be careful with it. THey don't make them anymore but people sell them on ebay
     
  6. Richard Jepsen

    Richard Jepsen Member

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    I have access to a Weston gage with the adjustment nut in the back. I adjusted that gage to match my old hard to read Kodak tank and tray thermometer. The adjustment worked great. The Weston gage is easier to read than a Premier gage. Thanks for the info, I never knew you could adjust the Weston.
     
  7. Mark Fisher

    Mark Fisher Subscriber

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    I recently bought a very inexpensive digital thermometer in ebay from Darkroom Source. It needs to be mounted in something...I made a hole in a pegboard in my darkroom and shoved it in. Very accurate and cheap....the downside is that it is fixed in one place over my sink. Although I can't misplace it either! I have a glass thermometer that I checked it against.
     
  8. RellikJM

    RellikJM Member

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    I purchased a replacement for the Kodak Process 3 here:
    http://www.icllabs.com/astmgenlab.html

    Part Number: 210-626 Extreme Precision - +30 to 124ºF in 0.1º increments 610mm length 3" immersion depth. With the themometer and case I spent about $125.
     
  9. fschifano

    fschifano Member

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    I don't know. I've been using cheap ($10 - $12 USD) kitchen thermometers for a long time now. I check them against a Paterson Color Thermometer and they all read within a few tenths of a degree F. In my book that's more than close enough and great value for the money. The dial thermometers are all over the place. Some can be adjusted, some not; and I don't bother with them any more.