Summary

Magnetic stirplate based on a 120mm fan

Instructions

Materials list:
(1)120x25mm standard computer fan
(2) rare earth magnets, 12.7 mm diameter 3.1mm thick, with 6.3mm hole
(1) stirbar
(1) 500 mL or larger erlenmeyer flask or beaker
(1) power supply 12vdc

How to build:
Wire up fan to 12 vdc supply, make sure it is clean and working.

Check the diameter of the case fan hub to be sure it fits in the spinner.
the magnets should be press-fit into the spinner, and then the spinner can be glued to the fan. I used silicone glue. Turn on fan, and make sure spinner is centered well

Put fan in case, andyou have a stirplate.

Use: put flask on top of plate before turning on power, otherwise the magnets will spin too fast and the stirbar can't keep up.

Stirplate