Let me preface with I am new to the forums. This place seems nice.
I'm running into an issue with my stir plate. When I rest my stir bar on top of the stir plate it will spin freely, and quickly, but when I place the stir bar into a flask with a liquid, the bar will not spin and throw to the side.
So, all of that being said, here are my stir plate specs.
Stir Plate Specs:
- Fancy switch thingy with red light
- 3/8" round rare earth magnets with 10 lbs. of pull force
- 1" stir bar with pivot ring
- Pyrex 2000mL flask - flat bottomed
2 magnets are mounted on a steel washer than has been epoxied to a small section of PVC pipe mounted to the fan. The poles are correctly setup so the stir bar will attach once brought into the magnetic field. The magnets are as close as you can get to one side of the project box that will allow the magnets to spin without rubbing on the top.
So here are my questions:
1. Should I swap my 12v power supply with a 6-9v range?
2. Does my fan spin fast because the 25 Ohm rheostat isn't doing much good? (Assuming so because at the lowest speed it seems to travel like a pack of gazelles)
3. Would adding more 3/8" round magnets to the magnet stacks increase the magnetic force/pull on the stir bar?
4. Does the added thickness of the flask really negate the magnetic attraction so much it causes the throwing?
Any help is greatly appreciated.