I am thinking of getting a balance to mix my own chemicals. I was going to get one of the lesser priced Acculabs like they sell at Photographers Formulary bu then I started thinking about mixing up PyroCat which has some ingredients that are .2g and the balances tolerance is .1g - not a good recipe for success. As always the thing complicating this is that I don't want to send a lot of money. Do you have any recomendations on good blanaces for around $300, or less, that are accurate to .01 grams or better. I don't mind used, but I don't know what to look for/ask when buying with e-bay.
I prefer a digital balance since that is what I am used to from college chemistry, but a true balance would be fine if it is accurate enough.
I'm using a digital postal scale - I solved the tiny quantities in Pyrocat HD problem by simply mixing more. The formula is for 100ml, if I remember correctly - I mix 1000ml. Multiply everything by 10 and the quantities fall into a range that much less expensive scales can measure.
Also, there are inexpensive scales on ebay that measure fractions of a gram.
I purchased my Ohaus Triple Balance on E-Bay for $60 + shipping.
I had researched:
HOT BUYS - Balances: http://balances.com/
EDMUND SCIENTIFICS: http://scientificsonline.com/
All of which brought me back to E-Bay and the reliable, accurate and much less expensive Triple Beam.
I got a digital balance a year or so ago. +-.01. I will check tomorrow when i go into the lab to find out the name of the company . At one time it was bookmarked but have changed computers since that time.
I have been very happy with it and it was about 125 dollars. What i do remember is that this company makes all types of scales, commerical, etc.
Try Fisher Scientific. They sell a variety from research grade to teaching lab grade. You may also wish to see whether your local college periodically cleans out and sells old equipment. Occasionally a mechanical Mettler balance (with the agate knife-edge) will show up, as they're considered too masochistic to use these days. I have one from a previous lab demolition,and it's a nice balance, though the 0.0001 accuracy is probably more than is needed for mixing cyanotype.
Get a gunpowder scale for the really small quantities. They measure in grains, with 1 gram = 15.4323584 grain. Quite accurate. The only downside is when you have to measure large quantities - it can take a while, since the balance is really made to measure small to tiny amounts.
But, it works. I've used it many times to mix up Pyrocat-HD.....
Ditto the recommendation for a gunpowder scale. Lee's is a bargain, accurate and consistent. RCBS's is better made, tho' not necessarily more accurate, and priced proportionately higher.
You can also buy powder tricklers to add minute amounts to the scale cups.
RCBS is the brand I have, and it works well. I only mix Pyrocat-HD with it, and I haven't made any of that in a while, so it's just been sitting...