Help with my Cigar Stir Plate

[randomgnarkill]

I've been having so much trouble trying to make this stir plate to work right. I could get it to about 1/4 speed before the stir bar jumps off. I've looked online and tried plenty of things.
It's a 1" stir bar
2000ml flask
Pulse controller
Earth magnets from computer.
?s
Can the lid be to thick with the cloth.
Is my stir bar too small
Thanks for your help

 

[randomgnarkill]

Pics

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[day_trippr]

I think the button magnets may be a bit too far apart for optimal performance.
They're so close to the ends that one of them is probably "losing its grip" if the bar moves just a little off center.
That leaves the bar pivoting on the other magnet and it likely gets tossed before half a rotation...

Cheers!

 

[randomgnarkill]

Thanks I'll try them closer. I've try the button magnets and also the earth magnets from a hard drive. I know it's a small tweak of some sort I just don't have the experience. Thanks

 

[mainiac]

Try using one of the octagonal stir bars with the molded ring in the center . . . My stir plate gave me fits until I switched to one of these . . . It can still throw the bar if I ramp the speed up too quickly, but overall very stable.

 

[randomgnarkill]

Ok thanks I'll try the spacing first then the stir bar.

 

[day_trippr]

fwiw, I think button magnets are less than optimal.
I use broad-side polarized bar magnets, 1x.25x.1" N40 (Magcraft NSN0834/N40), and my two stirrers can swing 1" to 2" generic bars at full speed without issue, even when the yeast has thickened at the end of the stir.



The entire face of each magnet is a pole so it's pretty clear why they work so well...

Cheers!

 

[randomgnarkill]

I tried magnets from hard drive pictured. Do you have any extra to sell me a couple at a low price? I only need 2 and $12 for 12 is steep.

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[day_trippr]

PM sent...

 

[randomgnarkill]

Running full force. Thanks day_trippr

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[day_trippr]

That's awesome!

And totally my pleasure.

Cheers!