DIY Stir Plate

[wolves63]

I have created a plate out of a cigar box, a 120mm fan, 12v 500 mA power supply, a pulse width modulator and a 1 inch stir bar and I haven't been able to get the stir bar to stay as it is spinning up. It starts great, but then will fly away from the middle. I have tried with and without water and still run into the problem. Any suggestions?


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[day_trippr]

You didn't mention what you used for the motivating magnet(s).

Otherwise, check your z-axis spacing from the magnets on the fan hub to the bottom of the flask. Too much spacing will cut the coupling force quite a bit...

Cheers!

 

[Ddubduder]

I found with mine that same issue was caused by an under powered magnet. Once I replaced it with a magnet from a newer hard drive and got it centered (as best you can) it worked flawlessly, even on uneven surfaces now.


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[cooldood]

If you have a stir magnet with a hub it will fly off easier.
I put some small o rings on the ends of mine and that fixed it.

 

[wolves63]

It is from a hard drive maybe 6 years old. Sorry about taking so long to respond life got in the way. The stir bar does have a ridge on it. Maybe placing 2 O-rings will fix it.


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[wolves63]

If you have a stir magnet with a hub it will fly off easier.
I put some small o rings on the ends of mine and that fixed it.

You are a life saver, my problem was that the hub was causing it to be unstable, the o-rings fixed the problem!

 

[flippedcracker]

Are you running it at full speed? 12v might make it spin too fast. I only needed an 8v ps.