Scales for photo chemistry?
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
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.
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/re...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.
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.
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.
Originally Posted by nworth
So far, so good, but we'll see how these scales hold up to years of use.
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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).
“Wise men talk because they have something to say; fools, because they have to say something.” - Plato
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.
Last edited by Ken Nadvornick; 07-17-2012 at 08:40 PM. Click to view previous post history.
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The First Officer then reaches out and confidently rings the engine room telegraph over to ALL AHEAD FULL...
— Captain Edward John Smith to First Officer William Murdoch, on the bridge of the RMS Titanic, 11 April 1912
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.
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.
my real name, imagine that.
I bought a small pocket scale from Lee Valley. Easy to use. So far, so good.
The fix is in!