A few questions on my stir plate build.

[itsme_timd]

Built a stir plate tonight and have a few issues with it. It works, but it doesn't seem to get up much speed and it also tosses the bar pretty easily. I have one of the bars with the raised band on it and I see on here that an o-ring on each end might help those.

My questions...

• I'm using a 6 volt power supply and the fan doesn't seem to have much strength, should I kick up the power supply? (The fan is 120mm, if that makes a difference.
• Are my magnets big enough? They are rare earth magnets and seem to have some good pull on them but don't seem to be grabbing the bar that well.
• My LHBS only had 2" bars, I'm using a 1L flask, should I get a smaller bar?

UPDATE:
I upgraded to a 12v power supply and added an o-ring to the stir bar and it's throwing it almost instantly. I got a couple other magnets and the ones I'm using now are the strongest.

Anyone have any other suggestions to fix this?

Here's a pic of the magnets...

And here's an action shot of the plate. :rockin:

 

[kh54s10]

I used old power supplies from answering machines and similar items. The square box things that plug into the outlet. I tried a couple before I found the right - amperage? -. I also used a large magnet taken from a hard drive from an old computer. You might have to experiment a little with different magnets, placement, and stirbar size. It also seems that your fan is not turning very fast. You only need to make a dimple on the surface not a vortex going all the way to the bottom of the flask, but what I see in the video says that a thicker wort will not be stirred very well. Maybe it needs more power.

 

[itsme_timd]

I used old power supplies from answering machines and similar items. The square box things that plug into the outlet. I tried a couple before I found the right - amperage? -. I also used a large magnet taken from a hard drive from an old computer. You might have to experiment a little with different magnets, placement, and stirbar size. It also seems that your fan is not turning very fast. You only need to make a dimple on the surface not a vortex going all the way to the bottom of the flask, but what I see in the video says that a thicker wort will not be stirred very well. Maybe it needs more power.

Thanks, in the video I've only got it up about halfway because of it throwing the bar, however it does still seem underpowered to me. I have a few magnets but the ones I used were the strongest I had, perhaps I still need some a bit stronger.

 

[itsme_timd]

UPDATE:
I upgraded to a 12v power supply and added an o-ring to the stir bar and it's throwing it almost instantly. I got a couple other magnets and the ones I'm using now are the strongest.

Anyone have any other suggestions to fix this?

Should I move the magnets closer to the center? Add more magnets?

 

[day_trippr]

Add another pair of magnets inside the original pair. Make sure to match the poles!

fwiw, I have switched to using a pair of 1"x1/4"x1/8" n42 bar magnets, end to end and centered on the fan hub.

They're broad side polarized, so one entire face is a pole. With two of these working together I can use any size stir bar from under an inch to at least 2" and it'll stick like a kitten on curtains. I've yet to toss a bar...

Cheers!

 

[itsme_timd]

Thanks for the info. I'll try adding a couple more magnets and if that doesn't work I'll get the bar magnets.

I do believe the magnets are the issue as they seem to be fighting each other. Even though I made sure they all stuck to each other and to the stir bar it seems as thought they are having a bit of a push-pull battle.