Baynne (Stranger)
10-21-02 12:42
No 370798
      homemade magnetic stirrer?  Bookmark   

Hey guys,
   I've been looking around and can only find one reference to making magnetic stirrers.  It isn't very clear.  Is the magnet only magnetic on the ends?  Does the stir bar need to be magnetic so that the magnets attract or repel one another?  Or is the stir bar ferrous and attracted to the magnet which are both turned simultaneously via the motor?  I know this is a stupid question but I have no experience with magnetic stirrers and have a reaction I'd like to do involving  a few pounds of pressure and believe a magnetic stirrer would be better than a mechanical one.  Thanks for your patience and help on this
10-21-02 12:59
No 370804
      Rhodium's Page  Bookmark   

Have you looked at Rhodium's page yet? Magnetic stirrers are basically composed of a case, a magnet and motor to spin the magnet, stirbars are magnets sealed in plastic or glass  smile The link is :

../rhodium/chemistry /equipment/magstirrer.html

It's a lot easier to buy one than make one laughlaugh
(Chief Bee)
10-21-02 19:39
No 370912
      The stir bar needs to be a bar magnet coated with ...  Bookmark   

The stir bar needs to be a bar magnet coated with some kind of inert material.
10-29-02 10:57
No 373981
      Thanks Rhod and Lugh  Bookmark   

Thanks for the info guys.  I guess I'll just experiment and see what works for my situation.  Just one more question, what would be an ideal speed and size of the motor if one were to work with, say, a quart of not too thick liquid? Would the motor from a small fan work?  BTW, I'm one of those DIY guys.  I like to make things.
(Chief Bee)
10-29-02 11:38
No 373990
      rpm  Bookmark   

500-1000 rpm is good. The ideal is something allowing you to control the speed from 0-1500 rpm.

What does the "size" of a motor signify to you? Torque?
11-04-02 15:10
No 376336
      Does size really matter?  Bookmark   

Thanks Rhodium,
   By size I meant hp rating.  I really meant torque, but most motors aren't rated that way.  500-1500rpm is the answer I needed.  I really appreciate you guys.  Thanks.