DIY stir plate

[Paquitin]

I have encounter two problems. One is what is the best distance from the magnet to the surface were the flask is going to be on?Second is what stir bar size is best for a 2000ml beaker? I have one Hard drive magnet mounted in the center of the fan. Will appreciate the input.

 

[scone]

I have encounter two problems. One is what is the best distance from the magnet to the surface were the flask is going to be on?

The minimum you can manage. Raise the fan so that the magnet sits right under the surface.

Second is what stir bar size is best for a 2000ml beaker? I have one Hard drive magnet mounted in the center of the fan. Will appreciate the input.

Ideal stir bar size depends on your magnet dimensions. I use a 1 3/16'' stir bar with mine (also a hard drive magnet) but I think hard drives have slightly different magnet sizes. Also there's no telling whether or not I've picked the 'ideal' size stir bar. It works. :cross:

 

[bzomerlei]

If you are purchasing a magnet off the net, make sure you know the axis of polarity. I thought I scored a very nice magnet for my new 12" square based stir plate , but when I ran a test, the stirbar stood up at attention... The axis of polarity was through the vertical thickness, not the long axis as I assumed. I ended up using a magnet from a hd to get it up and working.