I built my own stir plate using a project box, electrical motor, potentiometer and on off button. I made a simple mount for the motor to the box, added a plastic disk to the motor's head and put two small size earth magnets positioned to the best of my ability aligned and balanced on the disk on top of the motor. When I test the stir plate without a flask and water it works fine, even with an empty flask it spins the magnet bar well. But, when I put water in the flask the stir bar spins to some point and then it ejects to the side of the flask. Anyone can help with that?
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