Stir Plate

I think we should make a kick ass Stir Plate like this!

-120mm comp fan
-25 ohm rheostat
-12V switch
-DC plug from a phone or similar 6 to 12V
-rare earth magnets or hard drive magnets
-stir bar
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A 12V DC fan such as found in PC power supplies. Other voltages will work if you have the right power supply.
Two rare-earth (strong!) magnets around 12x5mm. I bought mine from Alpha Magnetics in Boronia for 75c each (+GST).
Plastic plate (must be non magnetic) for the flask to sit on. Furthermore with the aluminium plate I first tried, although it didn't interfere with the magnetic coupling between the motor and stir bar, it really gave the motor a hernia so I resorted to wood. I will replace with perspex when I get a chance.
Misc machine screws and spacers. I ended up using 40mm M3 screws which allowed me to fit two 9mm spacers (threaded) to the motor and some M3 short machine screws to hold the platform down.
One or more stir bars. I made the mistake of buying the variety that has a ring in the middle to act as a pivot. Well unfortunately it pivots every revolution and the rattling forced me to leave the starter out in the garage overnight. I will be getting the "no ring" version very soon. I sourced these from Science Supply Australia in Mitcham. They also have conical flasks.
You will also need a suitable vessel for stirring in, such as a conical flask, ideal because it has a flat base. Common glass vessels typically have a convex bottom (looking at the inside) making it difficult to centre the stir bar.


http://brewiki.org/StirPlate

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http://www.thebitterbrewer.com/viewtopic.php?f=1&t=64
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www.stirbars.com