magnetic stir rods

[SunkenBier]

Quick question about magnetic stir rods.

Are they truely magnetic or just coated metal?
If they are magnetic, where are the magnetic poles located.
What shape magnets have people used in their home made stir plates?

Im hopping for magnets and think this one will be good for a stir plate.
http://www.kjmagnetics.com/proddetail.asp?prod=ZD9

[bub]

they are magnetic and the poles should be on the tips
I have used a crescent shaped magnet from a hard drive for my plate.
BUB

[Otterbrew]

My first attempt was with circular rare earth magnets, and if the magnet was centered on the fan hub, the fan wouldn't spin. I was able to move it off center, and the plate worked but it was loud (grabbed the stiring bar on the end as would flop all over the place). My wife didn't enjoy this new source of "Feng Sui". I have upgraded to HDD magnets (slight arc in the shape), and the performace is great: much better movement of the starter and it is quiet.

The combination that has worked best for me is the following:
120 mm medium spped computer fan (12 v)
6 volt power brick

Still need a better pot for speed control, little resolution in the one I purchase from Radio Shack.

-Otterbrew

[mfischer2]

Quick question about magnetic stir rods.

If they are magnetic, where are the magnetic poles located.

The poles are on the NORTH and SOUTH end of the magnet.

Glad I could be of assistance.