How To Make A Stir Plate for about $15 - Part 2
This video shows how you can make a stir plate, including magnetic stir bar for less than $15. Earlier we hooked up a PC fan to a power supply. Here we cut the table from plastic (thin wood would work too if that's what you have), do a little drilling, assembly, and adjustment. Then play with it!
Tools and supplies: thin plastic or thin plywood, scoring tool or something to cut your sheet goods, drill bit, counter sink bit (or large drill bit), four 2 inch bolts and eight nuts ($1 at the hardware store), two rare earth magnets (Harbor Freight sells 10 for $1.49), one stir bar (eBay sells them for $5), glue (I used "Blu-Tack" so I could reposition the magnets, but if you use the 25mm stir bar, you can make them 1.4mm apart [2.2mm center to center]).
I won't try to explain the benefits of a stir plate when it's time to make your yeast starter...it's quite amazing to get billions more cell bodies and get your fermentation off to a great start.
EDIT: I should have said 14mm, above, not 1.4mm, and 22mm, not 2.2mm.
EDIT2: The two little "pill" magnets can work, but it's very sensitive (stir bar gets thrown easily). The solution is to dig a crescent shaped magnet out of an old hard drive and use that.