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ackiefan87
Lizard farmer
Registered: 02/25/10
Posts: 35
Loc: between the flat one and ...
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Homemade magnetic stir plate/ stir bar compatibility issues?
#12399996 - 04/15/10 08:29 PM (13 years, 11 months ago) |
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Does anyone use stir bars like these http://www.amazon.com/Fisherbrand-Octagonal-Magnetic-Stir-Surface/dp/B0017YCDC6/ref=sr_1_1?ie=UTF8&s=industrial&qid=1271383769&sr=8-1 with homemade stir plates using hard drive magnets? I found a couple of these and figured I'd give it a shot. My stirrer works OK with bits of wire, but when I put these in they just bounce erratically or lodge themselves in a corner no matter what the speed is set at. Is it a polarity issue? Maybe the wrong kind of magnet? I've tried with a 1", and a 2" bar with the same results.
-------------------- "Now, I may not understand it, I may not necessarily agree with it, but I'll tell you what, I accept it, just sort of glide along. You want to keep things on an even keel, I guess it's what I'm saying, you want to go with the flow. The sea refuses no river. The idea is to remain in a state of constant departure while always arriving. Saves on introductions and good byes. The ride does not require explanation, just occupance, that's where you guys come in." -BCG http://www.shroomery.org/forums/showflat.php/Number/12480081
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PrimalSoup
hyperspatial illuminations
Registered: 11/17/09
Posts: 13,568
Loc: PNW
Last seen: 1 year, 6 months
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Re: Homemade magnetic stir plate/ stir bar compatibility issues? [Re: ackiefan87]
#12400252 - 04/15/10 09:21 PM (13 years, 11 months ago) |
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The magnets are polarized differently than you probably think, is what's happening. Try it out with a loose magnet and the stirrer bar until you figure out the right arrangement than lock that in on the stir plate. Or get a different magnet for the stirrer, the HD ones are Neodyms and you can get Neodyms of any size and shape you want easily online. Even teflon coated as cylinders for exactly this app...
Peace -PS
-------------------- if you stand too close to the machine it'll start to eat youPrimal's simple tested teks and projects: Wheat Prep 2.0 Acidic Tea Tek Potency Project!
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drumjam
Strangest
Registered: 01/15/06
Posts: 248
Last seen: 8 years, 7 days
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Re: Homemade magnetic stir plate/ stir bar compatibility issues? [Re: PrimalSoup]
#12401508 - 04/16/10 01:05 AM (13 years, 11 months ago) |
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Had the same problem, and I use those bars. It could be the mag that your using in the stir plate but I found that it's the curve bottom of the jars that are the problem with these bars.
For me I start off slow and the move up, sometimes it takes a few tries.
The only other thing I could think of is that the polarity of the plate mag is off. I made mine longer in order to create a wider field and that help.
GL
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Solipsis
m̶a̶d̶ disappointed scientist
Registered: 12/28/09
Posts: 3,398
Loc: the Neitherlands
Last seen: 7 months, 15 days
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Re: Homemade magnetic stir plate/ stir bar compatibility issues? [Re: drumjam]
#12402637 - 04/16/10 08:53 AM (13 years, 11 months ago) |
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I have this problem but only a little. Sometimes the stirring bar is just shaking somewhere but I think it's because the rotating magnetic field is not perfectly balanced or centered. If I get the rod/bar in the right place it rotates and stirs though, because I did my best to get my neodymium unit in the center. I did that by testing it before glueing, shifting the position to get the bar in the center, it doesn't mean that the magnet itself has to be in the center, it has a weird shape and therefore probably a warped magnetic field.
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ackiefan87
Lizard farmer
Registered: 02/25/10
Posts: 35
Loc: between the flat one and ...
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Re: Homemade magnetic stir plate/ stir bar compatibility issues? [Re: Solipsis]
#12406644 - 04/16/10 10:28 PM (13 years, 11 months ago) |
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Thanks guys! You've given me a lot of ideas to play around with. I'm sure I'll come up with something, and if not wire bits it is.
-------------------- "Now, I may not understand it, I may not necessarily agree with it, but I'll tell you what, I accept it, just sort of glide along. You want to keep things on an even keel, I guess it's what I'm saying, you want to go with the flow. The sea refuses no river. The idea is to remain in a state of constant departure while always arriving. Saves on introductions and good byes. The ride does not require explanation, just occupance, that's where you guys come in." -BCG http://www.shroomery.org/forums/showflat.php/Number/12480081
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