Help with DIY Stirplate

Hey all —

I've been trying to build a stirplate... I've the electrical taken care of... I'm trying to use hard drive magnets on a run of the mill computer fan.

I've seen the forums about using a washer, which I've done. I can't seem to get this thing aligned correctly.

I turn the fan on slowly (it needs more juice to get started, but I back down the speed right away). I slowly speed the fan up, but before I can get any sort of stirring action, the stir bar flings off.

I've tried getting closer to the fan, but the fan then sticks to the bottom of the flask...

Here are some pictures. The magnets in this shot are one of several dozen orientations. Then, these are the two stir bars I'm using, from Austin Homebrew. One is 1", the other is 2".







Any thoughts?

Cheers!

I tried all sorts of thing with mine, I had the most success with just one hard drive magnet centered on the fan and a very small stir bar

I've tried one magnet on the washer, and again without the washer... Still no dice.

My smaller stir bar is 1" but it's not round. It's got a flat top and bottom. I wonder if I should find one of the football shaped ones?

If the speed of the fan is too great, the stir bar will get thrown. You don't need much speed to stir effectively. In fact, you don't even really need a vortex.

Also, convex bottoms on glass jugs and jars will throw the bar with some systems.

The distance between the stir bar and your hard drive magnet(s) is also important. Not knowing what you're using, it's hard to say what's going on. Good luck with it.

I had the same issue, I ended up placing my magnets end to end in a line. One facing up and the other down. I then placed my flask with 2" stir bar over it to make sure the bar stays centered on the magnets and not just over one or the other. If this does happen then just flip the magnets around and check your stir bar allignment over the magnets again. Eventually you will turn them the right way. the ends of my magnets do not touch, they are about 1/4" apart. Good luck on your build.

I'm trying to picture your set up. I glued a metal coin size punchout piece to the center of my fan. then I used a hard drive magnet on top of that. You can then move the magnet around to different positions until you find one that works. Can you play around with the position of the magnet?

I cut out a 2.5" circle out of scrap MDF wood I have. I have 6 button magnets purchased from Ace Hardware for less than $6. I will use 2 magnets per each side of the circle and countersink them.

magnets are STRONG as F uck... I should definitely be able to spin a stir bar using this method.

-=Jason=-

My fix was very simple. I moved it from the counter top to the carpet. It stoped throwing it then.

I would suggest experimenting with different size stir bars. Take some steel nails and cut them down to different sizes to test out. I had to find the perfect size for my DIY stirplate, not too big and not too small. Once you find the right size get some small home depot plastic tubing and melt the ends with the nail inside it. Whalla, you have your own DIY stirbar.

bovineblitz said:

I tried all sorts of thing with mine, I had the most success with just one hard drive magnet centered on the fan and a very small stir bar

Click to expand...

+1

Put the magnet(s) across the center of your washer and use the smallest stirbar. Place the flask with stirbar inside on top of your stirplate BEFORE turning it on. Switch it on...

HarkinBanks said:

I would suggest experimenting with different size stir bars. Take some steel nails and cut them down to different sizes to test out. I had to find the perfect size for my DIY stirplate, not too big and not too small. Once you find the right size get some small home depot plastic tubing and melt the ends with the nail inside it. Whalla, you have your own DIY stirbar.

Click to expand...

Eh... I would stick with the stirbar. The magnetized stirbar definitely performed a lot better than any non-magnetized material I used...

Hmmmm, I like the idea of mdf. Mainly cuz I think the magnets could be interfering with the fan motor.

I'll play with that tomorrow.

Any idea why moving the vessel to the floor helped? That sounds odd to me.

Thanks for the input everyone. I'll post my next test results soon

I played around with the magnets a long time before getting it right. I used a 9v supply but wasn't satisfied with the vortex..so I added a 12v supply and the bar was getting thrown. All I did is I added another magnet stacked directly on top of the original magnet. I centered it the best I could and now I can jack it up full speed and get the vortex to the bottom of the flask no problem.

Good luck...I'm sure with enough adjusting you will get it working.

mine -

1) Hard drive magnets held off the motor with some plastic - they were interfering with the motor turning. It took too much 'juice' to get it turning.

2) Flask held half an inch (maybe more) from the turning magnets. Small stir bar.

as stated above, vortex not required - swirling is all that is needed - you're keeping the yeast in suspension. nothing wrong with a slow-n'-steady operation.

butler1244 said:

All I did is I added another magnet stacked directly on top of the original magnet.

Click to expand...

That did it! This thing is now idiot proof. I flip the switch, and it goes, and keeps going.

Though, um, I may have dumped my stir bar in my carboy today.

So, next step is to find a better way than electrical taping the fan to my dining room table, then throw a Gladware bowl on top of it. :-D

scsi said:

That did it! This thing is now idiot proof. I flip the switch, and it goes, and keeps going.

Though, um, I may have dumped my stir bar in my carboy today.

So, next step is to find a better way than electrical taping the fan to my dining room table, then throw a Gladware bowl on top of it. :-D

Click to expand...

Nice.

To remove my stirbar/prevent it from going into the carboy, I use a rare earth magnet to hold it to the side of the flask when I pour

The thing I that found for my plate was that my 1" stir bar was too big I needed a 1/2" stir bar.

Ooh I just tested mine with an extra hard drive magnet on top of the one that was already there. I can use a bigger stir bar and it makes a lot less noise. I raised the height at which the flask sits above the fan with some screws inserted into the holes at the corners of the fan, worked great.

Thank you thread!

bovineblitz said:

Ooh I just tested mine with an extra hard drive magnet on top of the one that was already there.

Click to expand...

Glad that you and scsi got your stirplates working. It was definitely driving me crazy so I'm glad the extra magnet stacked on top helped!