Home of the BrewNosers

I assembled and tested my stir plate the other day and it seemed to work fine.

However it constantly throws the magnet, I have a pc fan speed controller hooked in line to control the voltage (really touchy but it seems to work), and for magnets im using 2 small rare earth magnets from Princess. The magnets seem balanced on the fan, it doesnt wobble or vibrate at all

any suggestions?

to clarify, it throws the magnet generally just as a vortex is starting up

What size stir bar are you using?

You may need stronger magnets on your fan. I'm using a stack of 3 x 1/2" magnets on each side (total of 6) of these on my homemade stir plate.

http://www.leevalley.com/en/wood/page.a ... 2363,42348" onclick="window.open(this.href);return false;

Still very temperamental...but that being said...I borrowed Pete's real stir plate last week and could not get it to work with a 2.5L starter in a 5L flask. It was doing the same thing you describe...throwing the stir bar once the vortex started. I ended up going back to my homemade stir plate. I'm thinking about getting some stronger magnets as well as a stronger stir bar to see if that helps any.

thanks, thats probably my issue, im using one 8mm magnet on each side, ill try a stack and see how that goes

that did it, thanks

and now I think the potentiometer is dead. Where did anybody else get theirs? My cheap Chinese ebay purchase is dead

I got mine from still dragon when I ordered my controller. It doesn't work great though...had 2 speeds...on and off...I can't control the speed whatsoever. Likely overkill for this build.

http://stilldragon.com/index.php/potentiometer.html" onclick="window.open(this.href);return false;

I'm using a dimmer switch with a 120V computer/overhead projector fan, a 2" bar and two 1/2" rare earth magnets, all mounted on the bottom of a bucket.