Magnetic Stirrers?greenspun.com : LUSENET : Large format photography : One Thread
I have been disappointed with less than optimal disolving of powder chemistry, such as Dektol, after seeing solids floating in the amber bottles and am considering a magnetic stirrer as a potential solution. Has anyone else encountered the same problem and what have you done to insure complete dissolution of the chemistry?
Looking at the magnetic stirrers, the larger the size obviously the higher the price. Is it possible to use a less than 1 gallon stirrer and after securing effective disolving of the powder, simply dilute the saturated solution to proper levels without problems?
Thanks in advance.
-- Michael Kadillak (firstname.lastname@example.org), October 09, 2000
Thinking much as you are, I bought a magnetic stirrer once and found that it wasn't a very wise purchase. Using the stirrer saved on my forearm, but it didn't mix very vigorously and I got equally tired of slowly pouring chemicals into the beaker. What was worse, the whirligig didn't seem to promote complete disolving of the chemicals any more than manual stirring. I ended up lining my funnel with paper coffee filters to remove most of the undisolved grains, but I won't swear that eliminated every last one either.
-- Steve Singleton (email@example.com), October 09, 2000.
Having seen these in labs at school, I purchased a used one at a local scientific supply outlet. It cost me about $150. For me, it was worth it. It's magnetic stirrer is approximately 2 inches long, and it has no problem mixing a gallon of Dektol solution. It only takes 15 or 20 minutes.
However, as with manual mixing, I also get some leftover particals (or precipitate?) at the bottom. So, I filter these impurities as I pour the solution into my stock containers. I use a six quart container for the mixing.
-- neil poulsen (firstname.lastname@example.org), October 09, 2000.
How much does a paint stirring attachment for a cordless drill run?
-- Sean yates (email@example.com), October 09, 2000.
I was checking out a chemical laboratory supply site here in Germany, also looking for a magnetic mixer. I found that those are not the only types of mixers used in labs for dissolving powdered chemicals. They also offer what amounts to a kitchen mixer (food processor), the kind that looks like a stick with a blade on the end. Of course they are much more expensive than the ones found in the housewares dept. of a Walmart. But why wouldn't an ordinary household appliance like this work. Even the old fashion egg beater might be an effective alternative to a glass rod. I'm going to give one a shot. But don't tell my wife...please!
-- William Levitt (firstname.lastname@example.org), October 10, 2000.
One more thing. There are also many different sizes and shapes of magnets available for the mixers. Some even carry the name "Turbo" which could lead to a more effective mixing of the chemicals than an ordinary magnetic "stick".
-- William Levitt (email@example.com), October 10, 2000.
Michael you may wish to consider a heated magnetic stirrer although more expensive they much more efficient. Regards,
-- Trevor Crone (firstname.lastname@example.org), October 10, 2000.
When I was at University, we used to use water as hot as the tap would yield when we made up Dektol or D-76. When the water is hot the chemical goes into solution very easily. Sometimes there are little bits of white stuff floating around in freshly mixed solution but these go away once it cools.
I tried to use a magnetic stirrer once with water at Kodak's reccommended temperature and it took forever to mix. I was also concerned that I was aerating the solution for an extended period of time.
So I still use the hot water system to mix powdered chemistry, and I haven't noticed any problems at all.
-- David Grandy (email@example.com), October 10, 2000.
The potency and quality of photochemicals is rarely comprimised when a few grains of undissolved chemical remains after mixing. These are most often impurities in the components, which are not reagent grade chemicals, and are inert and not harmful. Just pour your solutions into their storage bottles through a funnel with a fine mesh filtering screen if you want to get rid of the particulate (the chemicals will work fine with the particulates in them as long as they aren't so big as to scratch prints or negatives). Excercise your forearm muscles a little and save your money for something more important to the quality of your photographs.
-- Doremus Scudder (ScudderLandreth@compuserve.com), October 10, 2000.
Don't expect the mixer to do everything! I have one that was branded Nikor. It adequately mixes anything in a 1-gal. bucket. The magnet does make a big difference. Mine is round, with fins. You don't want it to work too hard, or it will bring in too much oxygen. Just set it so the vortex rises just below the surface. There's nothing wrong with using a stirrer everyone in a while to move unmixed chemistry into the middle where it gets mixed. I still say its far better than doing it by hand. If you want something to mix more than 1 gal. then you're in the professional league.
-- Alec (firstname.lastname@example.org), October 10, 2000.
Guys! $150.00 for a stirrir? I bought a cheap paint stirrer for an electric drill for $2, and the most expensive one they had cost $10. An electric drinks mixer costs $30 new, and a few bucks used at a thrift store.
-- Brian C. Miller (email@example.com), October 10, 2000.
Heated magnetic stirrers are the bomb. I wouldn't even bother with one that's not heated, because they don't dissolve things quicker than you would -- they just allow you to do other things while they work and prevent you from looking like Popeye. You don't need a big one because you can mix a gallon of Dektol (the only common photographic chemical I've found to be a pain) in portions.
I miss my heated magnetic stirrer...
Drill attachments aren't quite the deal they seem to be. They have to be made of stainless steel to prevent reactions with the chemicals, and they generally don't mix anything well in smaller than 2 or 3 gallon amounts. Good ones are pricey.
I've never seen anything for a Dremel, but that and the Dremel "drill press" would be a solution worth checking out.
-- John O'Connell (firstname.lastname@example.org), October 10, 2000.
I advise against a common paint stirrer unless it is plastic, plastic coated, or 316L stainless steel. Regular steel is bound to contiminate the solution.
Also, don't using any stirring method that adds a lot of air. This will make the solution degrade faster.
The easiest way to avoid the problem is to use liquid concentrates.
-- Charlie Strack (email@example.com), October 10, 2000.
I have both a Dremel tool and its drill press, but I'm not sure about using it as a stirrer. The Dremel runs fairly fast at its low setting, much faster than my 1/4" variable speed drill. Also, the Dremel chuck is quite small and the stand is short. I'm not sure that the setup would work well with a 1-gallon pail.
I wonder how a submersible pump would do. There is a small unit available from a local hobby store, and it runs on 12VDC.
There is a liquid plastic, I think it's called "Plastic Kote", which can be used on various things to give them a plastic coating. I don't know how it would react to various photo chemicals, though. Come to think of it, a plastic electric fan blade could be attached to a plastic rod, and then to a fan motor with a variable speed control. That should work well.
When I mix chemicals, I have found my best results come from mixing them at Kodak's highest recommended temp. I just heat the water on the stove first.
-- Brian C. Miller (firstname.lastname@example.org), October 12, 2000.
Forget that, I need to know about 600rpm air motors. Hit me.
-- Nick Woods (email@example.com), October 15, 2001.
I'm only twelve so I don't need to worry about that, I have these questions on particals and one of them is: Why do particals move faster in hot water? All I know is that when the particals move they cause energy and friction but I don't know why they move around. Just wondering if any of you could answer it now. its due tomorow. sincerly, Mike S. P.S. sorry about the email. its kind of long.
-- Mike Salsbury (firstname.lastname@example.org), November 14, 2001.