I made a magnetic stir plate completely from spare parts I had just laying around. Compare that to a $160 commercial stir plate from one of my favorite online homebrew stores and I saved a bundle! I grabbed the idea from HomeBrewTalk, but mine is a bit simplified (no power switch or potentiometer).
WARNING: Do not work with electricity unless you follow proper safety precautions!
Stir plate equipment needed:
- 1 case to mount fan / hold starter
- 1 computer case fan
- 1 AC/DC power adapter
- 1 large rare earth magnet (computer hard drive magnet)
- hot glue / hot glue gun (used for mounting fan against the roof of the casing)
Stir bar equipment needed:
- 1 small gauge broken drill bit (or similarly small gauge cylindrical metal object)
- slightly larger gauge insulated wire
- hot glue / hot glue gun
Stir Plate Method:
- Drill air flow wholes into fan chasis so that the lack of airflow doesn’t burn out the fan
- Place magnet to the bottom of the fan motor (since it’s a magnet and it’s attaching to an electric motor you shouldn’t need any adhesive)
- Hot glue the fan to the top of the casing (making sure the fan is uninhibited from turning and the magnet side is against the case)
- Connect the AC/DC adapter to the fan
Warning: Make sure you use DC output that is compatible for the fan (not too high or you could burn out the fan)
Optional: If you want a variable speed you can put a potentiometer control inbetween the AC/DC adapter and the fan
- Close up your case and plug it in.
- Cut the wire to size just longer than your small gauge cylindrical metal rod (in my case a broken drill bit)
- Remove the conductive metal from the insulated wire
- slide cylindrical rod inside plastic insulation
- Inject hot glue into the ends to keep water from contacting the metal and causing rust