Magnetic Stirrers, anyone using one?

Discussion in 'Darkroom Equipment' started by Robert Ley, Jul 7, 2013.

  1. Robert Ley

    Robert Ley Subscriber

    Messages:
    252
    Joined:
    Jun 9, 2004
    Location:
    Buffalo, New
    Shooter:
    Multi Format
    I am considering getting a magnetic stirrer for mixing dark room chemicals. I have checked them out on Evilbay and there are two kinds. One justs stirs and the other heats and stirs. Obviously the one that also heats would be great if you start with room temp distilled water, but I have a microwave oven heater for that.

    I guess what I would like is your experience and the model that you use or recommend. I think that a 2lt capacity would be OK, but if it could handle a bucket that would allow a 1gal - 5ltr mix would be great too.

    Thanks for any help you can give me in my decision.
     
  2. Lowly

    Lowly Member

    Messages:
    45
    Joined:
    Feb 10, 2012
    Location:
    Australia
    Shooter:
    Multi Format
    After having a problem with the time taken to mix the 5ltr packs I invested in a cheap non-heated magnetic stirrer from the auction site that could handle 5 litres. It's made life much easier! It would be nice to have a heated one but the stirrer's quite efficient so the solution doesn't lose too much heat while it's stirring. Definitely worth it to me.
     
  3. Robert Ley

    Robert Ley Subscriber

    Messages:
    252
    Joined:
    Jun 9, 2004
    Location:
    Buffalo, New
    Shooter:
    Multi Format
    Who is the manufacturer of your 5ltr mixer and what is the model number?
     
  4. ann

    ann Subscriber

    Messages:
    2,923
    Joined:
    Sep 10, 2002
    Shooter:
    35mm
    Have been using one for almost 30 years.

    The chemistry teacher at a high school I taught for many years ago use to mix my chemistry for class and then when I moved I got one for myself, and that was in 1984
     
  5. mwdake

    mwdake Member

    Messages:
    616
    Joined:
    Aug 25, 2007
    Location:
    FL, USA
    Shooter:
    Multi Format
    I have a magnetic stirrer, no heater with it though.
    I find it most useful for mixing hard to dissolve items like the potassium carbonate in Pyrocat HD.
     
  6. cmacd123

    cmacd123 Member

    Messages:
    1,495
    Joined:
    May 24, 2007
    Location:
    Stittsville, Ontario
    Shooter:
    35mm
    They are hard to do without. The heater would be a nice touch, but I get along with a plain one. Don't forget to get some Teflon magnets.
     
  7. craigclu

    craigclu Subscriber

    Messages:
    871
    Joined:
    Sep 8, 2002
    Location:
    NW Wisconsin
    Shooter:
    Multi Format
    I'd sure promote it for you. I use a heated version and wouldn't be without the heater, personally. Resist the urge to over-speed the magnet as it will cavitate air into the mixture. Just keeping things in motion is sufficient. With heavier loaded powder like Na2SO4, it could require a little manipulating of your mix container around the spin point of the magnet to get the corner material moving but a bit of patience helps (and it sure beats hand mixing!).
     
  8. Gerald C Koch

    Gerald C Koch Member

    Messages:
    6,461
    Joined:
    Jul 12, 2010
    Location:
    Southern USA
    Shooter:
    Multi Format
    Have used the same one for 40 years. I find it indispensable. Beats elbow grease.
     
  9. heterolysis

    heterolysis Member

    Messages:
    175
    Joined:
    Sep 21, 2012
    Location:
    Hamilton
    Shooter:
    Multi Format
    I use a hot plate with a magnetic stirrer. Works great for C-41 chemicals, even up to 5L, though the beaker takes forever to heat.
     
  10. Ken Nadvornick

    Ken Nadvornick Member

    Messages:
    5,004
    Joined:
    Mar 18, 2005
    Location:
    Monroe, WA, USA
    Shooter:
    Multi Format
    I use this Corning PC-420D hotplate/stirrer kit* and would never go back to manual mixing. In fact, after having carefully watched liquids of differing densities being mixed in a beaker by this unit, I quickly came to realize just how poorly I had been doing it by hand. It takes more effort and quite a bit longer than one might think.

    I also found it to be much more efficient to purchase and use an inexpensive kitchen hot plate and water bath to initially raise the temperature of bulk liquids to at or near the desired temperature, then transfer over to the Corning unit for temperature maintenance and stirring. It's a two-step process, but greatly speeds things up.

    Ken

    * I got it new, but didn't pay anywhere near that MSRP price!
     
  11. artonpaper

    artonpaper Subscriber

    Messages:
    326
    Joined:
    Aug 7, 2007
    Location:
    Staten Islan
    Shooter:
    Multi Format
    I have a stirrer with a heater. It works great for most things. I got extra magnets and a wand for retrieving them from the graduate from Edmund Scientific. The only thing it doesn't do well is stir and dissolve ferric oxalate. Heating it to around 150º and putting a top on the bottle and shaking the heck out it for about 20 minutes is the only thing that works for me.
     
  12. StoneNYC

    StoneNYC Subscriber

    Messages:
    8,160
    Joined:
    Aug 5, 2012
    Location:
    Connecticut,
    Shooter:
    8x10 Format
    Can someone tell me what this is used for? Like, why is it magnetic? And what's it for? I've never had to "stir" before I just pour the chemicals in water, close the container, rotate it a few times and the working solution is ready to go... So ... I don't get it....


    ~Stone | Sent w/ iPhone using Tapatalk
     
  13. Ken Nadvornick

    Ken Nadvornick Member

    Messages:
    5,004
    Joined:
    Mar 18, 2005
    Location:
    Monroe, WA, USA
    Shooter:
    Multi Format
    It's used for mixing solids into liquids, or liquids into liquids.

    It's magnetic because the mixing is accomplished by placing the container to be mixed on top of a plate that covers a rotating magnet. A small magnetic mixing bar is then dropped into the container. When the mixer is activated the bar is twirled by the rotating magnet below the plate, thus mixing the container's contents.

    Fancier mixers also include a heating element below the plate so one can simultaneously heat and mix solutions. Many dry chemicals dissolve quicker and easier in warmer water.

    Ken
     
  14. Sponsored Ad
  15. StoneNYC

    StoneNYC Subscriber

    Messages:
    8,160
    Joined:
    Aug 5, 2012
    Location:
    Connecticut,
    Shooter:
    8x10 Format
    Oh, I've never had anything that needed a stirrer, but just bought my first bulk chemistry for mixing my own so maybe I'll have to get one...


    ~Stone | Sent w/ iPhone using Tapatalk
     
  16. Mike Wilde

    Mike Wilde Member

    Messages:
    2,933
    Joined:
    Aug 10, 2006
    Location:
    Misissauaga
    Shooter:
    Multi Format
    I don't recall the model number - it is years old and was bought for a good price used. Basic variac for speed control. You need to manually adjust the speed depending on if you have dumped in too much dry chemistry at once so the stirrier bogs down. Too fast, and it whips air into the solution, which is a nono for developers.

    I added a heater salvaged from Bunn commercial coffee warmer to the underside of the stirring platform. It works best to hold temperatures, rather than actually heating the solution in any reasonable rate. Usually I mix in a 3.8L stainless steel beaker, or a 2L pyrex beaker or erlenmeyer flask if the solution needs to stay hot and mix for a long time.
     
  17. Jim Noel

    Jim Noel Member

    Messages:
    2,165
    Joined:
    Mar 6, 2005
    Shooter:
    Large Format
    I would hate to be without a heated one.
     
  18. michael_r

    michael_r Subscriber

    Messages:
    6,614
    Joined:
    Feb 2, 2010
    Location:
    Montreal, Canada
    Shooter:
    4x5 Format
    Just keep in mind in case you don't feel like spending extra $ on a stirrer, it is a convenience, not a necessity. Most if not all the dry chemicals you'll be mixing will dissolve fine stirring by hand. I've never had a magnetic stirrer, although maybe one day I'll get one just for the hell of it.
     
  19. Robert Ley

    Robert Ley Subscriber

    Messages:
    252
    Joined:
    Jun 9, 2004
    Location:
    Buffalo, New
    Shooter:
    Multi Format
    I have gotten a lot of good information here. I have another question. I plan on using a 1000ml and 2000ml glass beakers to mix my chemistry. What size mixing bar works best relative to size and shape?
     
  20. edcculus

    edcculus Member

    Messages:
    270
    Joined:
    May 13, 2012
    Location:
    Greenville S
    Shooter:
    Multi Format
    Hey guys, just saw this. I've never used one for mixing photography or lab chemicals, but magnetic stirrers are a big thing in Homebrewing for making yeast starters. Basically, the stirrer constantly aerates the yeast starter so you have a large initial pitch into the unfermented beer.


    There are a lot people who have started making magnetic stirrers because the lab grade ones are either too expensive or too hard to find for the average homebrewer. Most that I know of are not heated. If you are looking for a good (cheap) stirrer homebrew yeast stirrers are a great place to start.

    I have one from Stir Starters. It works great for my purposes. I use a 2000mL erlenmeyer flask for making starters with this device. I think he also has instructions on a DIY version on the website as well.
     
  21. michael_r

    michael_r Subscriber

    Messages:
    6,614
    Joined:
    Feb 2, 2010
    Location:
    Montreal, Canada
    Shooter:
    4x5 Format
    I'm not sure how specifically a yeast stirrer differs from a lab stirrer in design, but aeration is definitely NOT what you want when mixing photochemistry.
     
  22. StoneNYC

    StoneNYC Subscriber

    Messages:
    8,160
    Joined:
    Aug 5, 2012
    Location:
    Connecticut,
    Shooter:
    8x10 Format
    Also I wouldn't use the stirrer in my yeast after using it in my chemistry... Haha


    ~Stone | Sent w/ iPhone using Tapatalk
     
  23. edcculus

    edcculus Member

    Messages:
    270
    Joined:
    May 13, 2012
    Location:
    Greenville S
    Shooter:
    Multi Format
    I'm not sure about design either. The speed is variable though, so if you were getting it to mix chemicals, you would just use a lower speed. For a yeast starter, you essentially want to get it going as fast as you can without throwing the bar. They also use the exact same teflon coated stir bars. I think the idea behind them is more economical than anything specifically designed for making a yeast starter. Afterall, there are plenty of homebrewers out there using lab stir plates too.

    Just thought this might be a good option as they are always available, and you don't have to hunt one down on Evilbay.
     
  24. edcculus

    edcculus Member

    Messages:
    270
    Joined:
    May 13, 2012
    Location:
    Greenville S
    Shooter:
    Multi Format
    haha, yea, I'd make sure to use separate stir bars and beakers!
     
  25. WHof

    WHof Subscriber

    Messages:
    23
    Joined:
    Jun 15, 2005
    Location:
    Chicago
    Shooter:
    Medium Format
    I got a Hanna HI 190M from American Science & Surplus in Chicago. It is certainly a hobby version but for about $40 it does the job. I did find, however, that a 1.5" stir bar works more efficiently than the 1" bar that comes with the unit.
     
  26. eclarke

    eclarke Member

    Messages:
    1,972
    Joined:
    Jun 11, 2004
    Location:
    New Berlin,
    Shooter:
    ULarge Format
    Have a nice, bought new, Corning hotplate stirrer. Best darkroom kit I ever bought.