For crying out loud-why wont my damn stirplate work right

[Test_Engineer]

If you guys are using the curved hard drive magnet, it is not exactly centered on the hub. iirc, it is slightly off to one side(toward the smaller radius side). I think I stuck the magnet to thin piece of round stock(a round screwdriver will work) and let it line up with the metal and drew lines down both sides of the piece of metal on the margnet with a thin marker to find it's "center". So at this point you should have 2 pararlell lines running down the magnet. Draw another one directly down the middle of those 2 to get a center line. Then draw one across the magnet in the skinny direction to make a cross at the center. I did this so I could tell if the magnet was spinning about its magnetic center. I then stuck the magnet to the hub of the fan and turned it on. I looked to see if the cross was going in a circle or spinning directly on center. Adjust it a bit by sliding the magnet around and turning it back on until I you get the cross to spin in place and not in a circular path. Once I got it to spin directly on center, I simpley place a few blobs of epoxy around the edge of the magnet to hold it in place for good.

[BeerMan]

took about an hour to build a double stir plate using hard drive magnets, 12v computer cooling fans, a pot resistor, a thin pine wood filing box, and a 12v power supply from Micheal's craft store. It was easy and works well not sure why some folks are having problems

[Brandt]

My Belco lab stir plate has the magnet offset. I will get the jumping bean syndrome some of you have described at higher rpms. But it is a matter of moving the flask around a bit to find the sweet spot. I don't have this problem with my 2L flask and the 1.5" stir bar. Only the 3/4" bar in my 50ml flask.

[TMB]

I had a problem with a MSBD once. The stir bar when all funnly like and I thought that I'd have to put the girl down and get a new one. Found out that if you get the stir bar too close to the hard drive magnet (like when your building a stir place) you can mess up the magnet in the stir bar. You might want to try a paper clip in the bottom of the flask and see if that works. If it does, ol' Bessie might need to be fixed.

[BadRock]

I thought that I'd have to put the girl down and get a new one.

That's one hell of a way to put it!

Poor ol' Bessie...