Stir bar/ Stir plate question

[Lars]

Can you screw up a stir bar by leaving it attached to a magnet? When I pitched my last yeast starter, I retrieved my stirbar with another magnet and left it attached. Now I cant get it to center on my stir plate and spin. Has anyone else experienced something similar?

[diver]

Some materials can become magnetized, not sure if what's in the stir bar is one of them. If it did you can demagnetize it by boiling it. I have two stir plates that I've left the stir bars on which is the same as leaving them on a magnet I think. I've never had a problem unless the speed was too high for the amount of starter in the flask. Starting out slowly and gradually increasing the speed helps.

[one_eye]

Lars,

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you guessed it - - $8.95 (or for free)

Only 3 in stock, act now to get yours today.


I knew these things would come in handy for something. ha.

P.S. Lars I have absolutely no valuable input about your problem

[GooberMcNutly]

Yes, attaching the N to the S for too long can neutralize the strength. Disconnect it and leave it alone for a while, and some may come back.

Or spend another $3 on a new stir bar.

[Thirsty Boy]

I dont know , but assume that the stir bars themselves are magnetised?? and that the poles are attracted to the opposite pole on the stirrer?

If so... you can re-magnetise your messed up stir bar by "stroking" it with your magnet.

See if there is any magnetism left in the stir bar (try to pick up a pin or something) if there is, work out which pole is which.

Take the north pole of your magnet, the stronger the better and "stroke" it down the side of your stir bar from its north to south pole. Repeat this many times and your stir bar should re-magnetise.

It would probably work faster if the stir bar was heated up a bit when you were doing it. Or I suppose you could heat the stir bar up quite hot, and just attach the magnet to the end of it while it was cooling down and for a week or so after. You could even introduce vibration of some sort which would also help (maybe)

Goddamn it.... poles, hot bars, stroking and vibration. I feel so dirty, its like I'm listening to lunchmeet.