Homemade Stir Plate Only Works w/ Homemade Stir Bar!?

I've been racking my brain and trying everything I can possibly think of but my homemade stir plate won't work with my $7 2-inch stir bar. I took a nail and a coffee stirrer and made a home-made stir bar and it works (not perfectly but it will get the job done).

I did it the same way everyone else does - pc power supply, fan, rheostat and a hard drive magnet, all in a cigar box.

I'm thinking if I buy a 1 inch stir bar it will work because the homemade stir bar is 1 inch but anything longer than the magnet itself doesn't seem to work

Anyone else had this same problem? Any suggestions? I've tried ceramic magnets but they didn't work, I've tried a variety of home made stir bars and some work, some don't. I want this thing to work with my store-bought stir bar although I think the coffee stirrer stir bar will be okay because it's completely sealed and the coffee stirrer is made to go in a hot beverage so I don't see how a little bit of star san or starter wort is going to hurt it.

I'm at a loss, any suggestions would be greatly appreciated.

Perhaps try spacing the magnets out further on the fan.

ahave said:

Perhaps try spacing the magnets out further on the fan.

Click to expand...

It's just 1 hard drive magnet, the curved kind. I played around with some ceramic magnets but they weren't strong enough.

I can get the 2 inch stir bar that I bought to spin perfectly on top of the box and inside an empty Erlenmeyer flask but as soon as I try it with a liter of water inside it gets thrown off after about 1 second and it won't work. I'm going to Home Depot to find a silicone O-ring that will fit my stir bar and see if that fixes the problem. I'll update the post a little later.

O-ring around the store-bought stir bar fixed the problem!!!!

I have the same problem... My stir plate works 100% with anything but my erlenmeyer flask. I can use a mason jar or a smaller Carlo Rossi growler, but as soon as I use my flask the bar will spin for about 30 seconds and just flop to the side.

does the stir bar match the length of your magnet? Stir bars are magnetized at the tips if the bar is longer then your magnet it will not spin right. I glued a big fender washer to my fan and placed 2 magnets onto that. That way you can adjust the magnets to match the stir bar.