Wed Aug 23, 2006 5:30 pm
I was tryin to follow the thread on B3 on building a stir plate. I am not an electrical engineer and had little success. So I went my own way. I took a fan out of an old computer and some magnets and got started. I used a cell phone battery charger for power and got the system to work. Knowing what I did, I went to the local electronics supply and bought a bigger fan and a rheostat that the owner suggested. I used an old floppy disk box to contain it. I glued on some magnets, very strong ones from a local hobby store, to the larger fan. Hooked up the rheostat and plugged in the power. I could not control the speed of the fan; it was either on or off and did not work. I went back to the thread and was totally confused by the instructions. I tried a different power supply with no luck. I then fell back on what I do know. I did not know what rheostat was right so I bought a dimmer switch and wired that to the power supply to the fan and removed the rheostat. This worked, however I could not get the fan to turn slow enough. I swapped the new larger fan out with the smaller fan from the computer. It works great. I would suggest that you have every thing on hand to build one, the distance from the fan to the flask is very important to give you enough magnetic pull without getting so much that the fan can not spin. I spent about 30 dollars on the plate, it would have been 10 had I not bought the unneeded larger fan and rheostat
