Scales for photo chemistry?

Discussion in 'B&W: Film, Paper, Chemistry' started by nsurit, Jul 17, 2012.

  1. nsurit

    nsurit Subscriber

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    I'm looking for a scale to weigh darkroom chemicals. I bought what can best be described as a drug dealers electronic scale on ebay. It isn't totally useless, just close to it. Any suggestions on specific scales folks have been pleased with using. The current range of stuff I am needing to weigh runs from a little watercolor for gum printing to fairly large amounts of silver nitrate for wet plate sensitizing. My best guess is a triple beam for heavier stuff and perhaps my drug dealers special for the water colors. If you are suggesting a triple beam, a specific model would be appreciated. Any suggestions on what to measure stuff into while weighing it? I tried a coffee filter on my elctronic scale for the silver nitrate. Boy, was that a disaster. Bill Barber
     
  2. dpurdy

    dpurdy Member

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    Ohaus is a good brand. I bought mine new at a scientific supply house. I see they are really cheap used on ebay. I use a plastic yogurt container as a cup to hold chemicals as I weigh them. I cut the yogurt container down till it weighs exactly 7 grams then I always add that to the weight I am after.
    Dennis
     
  3. SkipA

    SkipA Member

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    I use an Acculab VI-400 that I've had for many years. It is accurate to 0.1 grams, which I felt was adequate for my needs. Acculab has gone out of business as of January 2011, acquired by Sartorius Group. Sartorius makes a similar line of reasonably priced accurate scales. The prices seem comparable to the old Acculab line. I can vouch for Acculab, but I haven't used Sartorius scales so I can't say if they are comparable in quality.

    Here are some examples: http://scaleman.com/catalogsearch/result/?order=relevance&dir=desc&q=sartorius+ay

    As you can see, combining very high precision (0.01g) with high weight capacity (1000+ grams) is very expensive, but you can get 5100 gram capacity by 0.1 gram accuracy for $330. If you need greater than 0.1 gram accuracy, consider buying two scales. One low capacity scale with high precision and accuracy for miniscule measurements, and one less precise with higher capacity for those larger amounts where accuracy to a tenth of a gram is sufficient.
     
  4. nworth

    nworth Subscriber

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    I bought an Ohaus Dialogram about 40 years ago, and it's still going strong and is still very accurate. I have had problems with several of the cheap electronic scales that are now available. Be prepared to spend some money on a quality scale, and you will not be disappointed. Good scales are expensive, but they last and are easy to use.
     
  5. albada

    albada Member

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    And I was about to recommend the cheap electronic scales made by American Weigh and sold through amazon.com. I have two: A $20 unit with .01g resolution with a max of 100 grams, and a $70 one with .001g (milligram) resolution and a max of 10 grams. The $20 cheapo has seen a lot of use in the 8 months I've had it, and it's performed flawlessly. My complaint about the $70 unit is that it's influenced by nearby static electric fields on my fingers. It's accurate as long as my hands are over 6 inches away.

    So far, so good, but we'll see how these scales hold up to years of use.

    Mark Overton
     
  6. Leigh B

    Leigh B Member

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    Get a triple-beam Ohaus in good condition. Reliable and accurate over many years.

    If you're serious about your measurements, buy a set of mass standards (we call them weights, but that's not accurate).

    - Leigh
     
  7. Ken Nadvornick

    Ken Nadvornick Subscriber

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    I've used the same Ohaus Triple-Beam Balance for almost 40 years. So rugged it has sat perfectly zeroed for years now in the same spot, always ready for immediate use. Calibration masses say it's still accurate. Best part of all? It, too, is purely analog. An adaptation of one of the six originally defined classic "simple machines."

    In depth information and tutorials are available here.

    Ken
     
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  8. fhovie

    fhovie Subscriber

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    Electronic scales require a bit of faith - I sell scales and program them and integrate them with systems. If you get some test weights, you will learn if your scale is repeatable and linear. These are two things that cheap scales have trouble with. Acculab and Sartorious are among the better brands - Ohaus has their Asian cheapies and their German precision scales. Other brands like A&D are pretty good. Generally speaking, a scale that costs less than $100 is little better that a measuring spoon. A decent load cell alone is generally over $100. I use several in my darkroom, one is a GSE pharmaceutical scale that has 30,000 very reliable divisions and the other is an Acculab that is pretty good even at miligram increments - of course I have test weights and I check them - so there is not a lot of faith needed for mine.
     
  9. Mike Wilde

    Mike Wilde Member

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    I have the 'drug dealers' 0-50g' unit for small items. Do get the calibration weight. I had a set from a pan balance, and discovered that mine calibrates on 25 (and or - cant recall which) 50g.

    I also have a triple beam 0-610g.
    I use dixie cups for weighing boats, and tare them with a small length of wire hung off of the end of the beam in a hole meant for range extending weights.

    I also have lucked into buying an electronic balance meant for mixing auto paint tints 0-7000g in .1g scale for $2 that seems to be in perfect shape.
     
  10. walbergb

    walbergb Subscriber

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    I bought a small pocket scale from Lee Valley. Easy to use. So far, so good.
     
  11. Kirk Keyes

    Kirk Keyes Member

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    Any scale that's getting into the milligram resolution or better range is going to have some susceptability to static, as well as air currents. You can make a little enclosure out of cardboard to help deflect air currents.

    I've had good luck with the cheapo ebay digital scales. The two I bought 5 years ago read a set of certified weights nearly dead on. Not bad for $25 scales. The only problem is the one that reads to 1000g is smaller than the one that reads to 100g so you need to have a light-weight weighing boat to measure large amounts on it.

    Kirk
     
  12. BetterSense

    BetterSense Member

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    Another vote for Ohaus triple-beam balance. For what I have spent on cheap digital scales that last only a short time, I could have nearly bought an Ohaus and given it to my son decades from now.
     
  13. JPD

    JPD Member

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    I have a Acculab V-200 with 0.01g accuracy that I'm very pleased with.
     

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  15. Terrence Brennan

    Terrence Brennan Member

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    Good choice...I use the same model.
     
  16. fotch

    fotch Member

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    Analog all the way, Ohaus triple-beam.
     
  17. cmacd123

    cmacd123 Subscriber

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    I have played with a couple of Digital Scales now. My wife decided to get a real fancy one for her Kitchen, (What else who you expect from a retired engineer) and found that her reading seem to differ by the phase of the moon! the lower accuracy one she used to measure the Dog's Food tends to drift for about 20 minutes when started up and so she leaves it on all the time. I have a similar one to the "dog food" scale for my Darkroom.

    All three are from "My Weigh"

    Note that the electronic scales are calibrated by putting a SPECIFIC amount to weights on the scale. When I bought my first one I only bought one of the weights thinking that it was just used as a check, so had to go back and buy another weight. Order the set that the scale you buy needs at the start.
     
  18. albada

    albada Member

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    Looks like I'll need to take extra measures to isolate that scale from its environment. I don't dare even breathe near it!

    Mark Overton
     
  19. nsurit

    nsurit Subscriber

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    Thanks to all for responding. After searching options on eBay, I went to the Ohaus.com website to further research specifications and products and discovered they offered refurbished products with a 90 day warrantee. I bought the 760-00 scale at $87.95 including postage as opposed to $153.75 with free shipping on eBay for a new one. My expectation is I will be happy with the refurb and have an extra $65.80 to spend on chemistry and supplies. I feel very comfortable buying a refurb from the manufacturer. Bill Barber
     
  20. nsurit

    nsurit Subscriber

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    Ugh, got a call yesterday from Ohaus that their website was out of date and the scale I was ordering was not available as a refub. Order new one today and am sure I will be happy with it. Bill Barber
     
  21. Leigh B

    Leigh B Member

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    Refurb inventory changes daily.
    They may only have one or two refurb units at any given time, and when those are sold... no more until a new batch is finished.

    Glad you ordered a new one. It will last for many many years.

    - Leigh
     
  22. John Shriver

    John Shriver Member

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    I got a used Oahus JR 300 on eBay for $6.50, plus $10 postage. (From "Qwik Pawn" in Montgomery, AL.) Targeted at the jewelry/gold market (does troy ounces in one mode), but it also does grams. I presume gold buyers would not want an inaccurate scale. Range is 0-300 grams.

    I do need to get a 200 gram weight to calibrate it.

    Seems to be a reasonable product.
     
  23. Donbko

    Donbko Member

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    The option the whole meteorological information such as subgrid scale dynamical activities like disturbance and wet convection at every design time step is the benefit of the on-line process.
     
  24. paul_c5x4

    paul_c5x4 Subscriber

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    The United States Mint gives the weight for various coins. A cent =2.5g, a nickel=5g - A pile of these should be more than accurate enough to determine the accuracy of your scales.

    Other countries will have a government site where one can find the weights of local currencies.
     
  25. Ken Nadvornick

    Ken Nadvornick Subscriber

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    I was told as far back as high school chemistry that at 5 grams each US nickels were a reliable way to test a scale. At least at the level we were operating, which is about the same for a darkroom.

    Just for fun, I've done the test on my Ohaus Triple Beam (using stacks of nickels to multiply any systemic error) and it's always come out at 5 grams per coin.

    Ken
     
  26. Morkal

    Morkal Member

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    I think it is a best way to find out accuracy of your scale. But most of companies now offering certified scale with accuracy and you can easily adjust that scale Whenever you need.