Stir Plate Woes

I built a stir plate that works fine with a regular magnet in my erlinmeyer but when I put a stir bar into a wort starter it just gets thrown. I have tried both 1.5" and 2" stir bars. Any ideas on a solution? Larger magnets, slower motor speed? Did anybody else have this problem?
Its a great looking stirplate made out of oil finished mohogany, it just doesn't work. Help!

What plans did you use? I'm not 100% sure on what you are describing and I am not the stirplate expert, but it sounds like maybe the magnets on your fan/motor aren't strong enough to move the stir bar through liquid. Or as you suggested your motor may be turning too fast which could be slowed down with a rheostat wired into your system.

If you haven't done so, take a look at this thread, it provides a wealth of information on stirplates.

https://www.homebrewtalk.com/showthread.php?t=8850&highlight

does it work in water?

Sorry I wasnt clear enough. It works in water but only with a regular magnet, not the stirbars. I read the above link about a thousnad time but didnt build the voltage regulator circuit, just the simpler one that is linked to with the potentiometer.
The magnets that I glued to the fan arent huge but seemed to work fine when it came to moving the magnet I put in the flask.

Can you tear it apart and rig up a test run with the flask closer to the magnets?

the stir bars we use in my lab are magnetic....i'd go with what fifelee said, see if it is a distance issue. How many magnets did you put on the fan, hopefully only two at opposite poles?

I put two magnets at opposite poles from one of those magnetic name tag backers that people have to wear to identify themselves in retail/ restaurant jobs. the distance from the top of the magnets to the outside top of the stirplate is about 3/16th of an inch.
maybe I could just stick one more to the top of each magnet to make them more powerfull?

Is the fan turning when you put the flask on? This will make the stir bar "fly" off center.

Unplug or turn the stir plate off. Move the stir bar over the middle of the flask and turn it on/plug it in.

No I made sure that the fan was comletely stopped before I turned it on. I sure it does the same with all of the other stirplates where if the fan is moving the stirbar just jumps around when it is set on top.
I kind of think that the problem is either magnet size or speed of the fan at startup or a combination of both. the magnets are about 3/8" x 1/8" ea. and I feel like I should be able to wind the speed of the motor down to almost stopped but for some reason the three different sized potentiometers that I tried wont alow that to happen.

I had much the same problem until I jigged the speed circuit for a very slow start. I used an old Sun disk drive housing and had to tap into the voltage control circuit AND use an external dropping resistor.

The magnets I used at first weren't strong enough either (they were about the size you have). I ripped the magnets out of the old disk drive and they work great, but they are probably 10-20 times as strong as the first set.

I pulled apart and old, old, old hard drive but there was only one magnet in it. It was large but only one maybe I could break it in half and try to balance it as best as possible.
David, did you build the voltage regulator circuit or used some sort of existing circuit? what resistors did you add. I can build a simple circuit but it has been a long time since I designed anything and dont remember values that would help me out.