When looking around at all the random crap I have in my house for parts to build a stir plate, I ran across an old USB hard drive enclosure I hadn't used in a while. I figured I'd give this a shot as it has a wall wart and an internal power supply that could provide 12V, 7V, or 5V to power a fan. An 80mm muffin fan is about the same thickness as a 3.5 inch hard drive, so it should fit in there without any problem. The conversion took only a few minutes.
Here is a picture of the enclosure:
Loosen two screws and the drive mounting tray slides out. Here is a pic of the tray, with the stock cooling fan removed (it had burned up a while ago):
I stripped the ends of the wires for both the connector from the stock fan and the connector from the 80mm muffin fan, and twisted them together. I'll solder the wires later. This next shot shows the drive mounting tray with the new fan in place.
I drilled some holes in the bottom of the tray in order to mount the fan in place. The magnet I'm using is from an old hard drive. My plan was to epoxy it in to place, but I used some tape for testing purposes. It took me a while to get the magnet placed to limit vibration. Now that it's in place and nearly vibration free, I'm hesitant to replace the tape with epoxy.
This last photo shows the stir plate in action, creating a decent vortex in a mostly full 2L flask.
The fan I'm currently using is a 300mA 12V 80mm fan. It is being powered with 12V from the drive enclosure's power supply. I didn't try it with 7V or 5V, but I suspect neither would get the fan moving with the heavy magnet on it. I haven't yet decided if I will add a pot or rheostat to control rotational speed. I'll have to test it out with some wort first to see how it performs.
Here is a picture of the enclosure:
Loosen two screws and the drive mounting tray slides out. Here is a pic of the tray, with the stock cooling fan removed (it had burned up a while ago):
I stripped the ends of the wires for both the connector from the stock fan and the connector from the 80mm muffin fan, and twisted them together. I'll solder the wires later. This next shot shows the drive mounting tray with the new fan in place.
I drilled some holes in the bottom of the tray in order to mount the fan in place. The magnet I'm using is from an old hard drive. My plan was to epoxy it in to place, but I used some tape for testing purposes. It took me a while to get the magnet placed to limit vibration. Now that it's in place and nearly vibration free, I'm hesitant to replace the tape with epoxy.
This last photo shows the stir plate in action, creating a decent vortex in a mostly full 2L flask.
The fan I'm currently using is a 300mA 12V 80mm fan. It is being powered with 12V from the drive enclosure's power supply. I didn't try it with 7V or 5V, but I suspect neither would get the fan moving with the heavy magnet on it. I haven't yet decided if I will add a pot or rheostat to control rotational speed. I'll have to test it out with some wort first to see how it performs.
