Found a computer. Stir plate help.

[Justdrumin]

so I found this computer next to the dumpster and took it apart for the hard drive magnets. As I got to takin it apart I found this box that is the perfect size for a stir plate that has a power switch and a male end for the power chord as well as a decent size fan. I'm thinkin...JACKPOT!! I was hoping some more tech savvy people could help me here. In the pics below I'm pointing to the wires that go from the switch to this board which has a bunch of junk that the fan is connected to. Any reason I can't solder the fan to the switch, buy a power chord and wire up a speed controller to it? Here are some pics.

 

[Justdrumin]

Heres the power switch where I would wire up the fan to and remove the circuit board.

 

[Sudz_Makenzie]

That's pretty much what I did on one of my stir plate builds.

 

[bu_gee]

That box is the power supply. You'll want to be extra careful with liquids around that thing since there is high voltage in there.

Personally, I'd close that box back up and put it in another box and use it as the power supply for your stir plate.

 

[Sudz_Makenzie]

I should have said earlier .... I used the box, minus the circuit board and used a 12 volt wall wart to power the fan. I still used the switch though.:rockin:

 

[Justdrumin]

I should have said earlier .... I used the box, minus the circuit board and used a 12 volt wall wart to power the fan. I still used the switch though.:rockin:

Sorry, I put removing the circuit board as a caption to the second picture. You may not have seen it. I planned to cut the board off and wire the fan to the switch. I was wondering if a computer power supply would be too much to use with the existing switch and male plug. I planned to make the usual potentiometer and knob with it as well to control the speed. Then I'd need to dig up an old power supply chord from an old computer and presto! A free stir plate.

 

[number40fan]

The fan will need 12 volts to run.

 

[bu_gee]

Sorry, I put removing the circuit board as a caption to the second picture. You may not have seen it. I planned to cut the board off and wire the fan to the switch. I was wondering if a computer power supply would be too much to use with the existing switch and male plug. I planned to make the usual potentiometer and knob with it as well to control the speed. Then I'd need to dig up an old power supply chord from an old computer and presto! A free stir plate.

Removing the circuit board won't change the fact that there is still 120v in the box, not to mention the circuit board is what converts the 120vac to 12vdc for the fan, so now you have 2 problems.

 

[bu_gee]

Actually 3: Ferrous metal is pretty crappy for transferring magnetic fields. You'd be better off with a plastic, wooden, or glass surface between the fan-magnet and the stir bar.

Well, let's call it 2-and-a-half.

 

[Justdrumin]

Actually 3: Ferrous metal is pretty crappy for transferring magnetic fields. You'd be better off with a plastic, wooden, or glass surface between the fan-magnet and the stir bar.

Well, let's call it 2-and-a-half.

I was afraid of that. So maybe I'll just bypass the original power supply, use the switch with a 12v chord. The box has a big hole on top where the fan is mounted with a cage like cover for the fan. So I was gonna cut some of it to accommodate the magnet.

 

[Justdrumin]

Actually 3: Ferrous metal is pretty crappy for transferring magnetic fields. You'd be better off with a plastic, wooden, or glass surface between the fan-magnet and the stir bar.

Well, let's call it 2-and-a-half.

I was afraid of that. So maybe I'll just bypass the original power supply, use the switch with a 12v chord. The box has a big hole on top where the fan is mounted with a cage like cover for the fan. So I was gonna cut some of it to accommodate the magnet.

 

[Sudz_Makenzie]

Remove the ferrous metal fan protector and replace it with a piece of plexiglass. Countersink the plexiglass and use the existing screw holes in the box for a nice flush fit for the screws.

 

[Justdrumin]

Remove the ferrous metal fan protector and replace it with a piece of plexiglass. Countersink the plexiglass and use the existing screw holes in the box for a nice flush fit for the screws.

Very nice! That's a great idea. Very clean. I've seen a guy here that just cut the cover with no issues though. He used a USB fan that had an inline speed control on it. Not bad and very cheap, but I frequently make lagers and I make big starters. So I need something that will handle my gallon jug.

 

[Sudz_Makenzie]

Here's a couple of pics to show you what I've done. I put a thin piece of wood behind the metal to receive the power light and 25 ohm rheostat. Scavenged a hard drive magnet and glued it to the fan.

 

[Justdrumin]

Here's a couple of pics to show you what I've done. I put a thin piece of wood behind the metal to receive the power light and 25 ohm rheostat. Scavenged a hard drive magnet and glued it to the fan.

Man...that looks pretty awesome!! I love what you did. Is the plexi just mounted straight to the box or does it have a spacer between it. You've done a great job with it and I'll for sure be doin the same thing. Thanks for the help!!

 

[Sudz_Makenzie]

I used a nut as a spacer between the plexiglass and the metal.

 

[Sudz_Makenzie]

Also use a neoprene O ring above the nut. Also, if you look carefully, you can see another hard drive magnet stuck to the corner of the case .... that's to use on my flask when pouring the starter out so the stir bar doesn't end up in 5 gal of wort! Cheers

 

[Justdrumin]

Also use a neoprene O ring above the nut. Also, if you look carefully, you can see another hard drive magnet stuck to the corner of the case .... that's to use on my flask when pouring the starter out so the stir bar doesn't end up in 5 gal of wort! Cheers

Sounds good! Any issues with the plexi flexing with your flask on it? Do you ever make big starters like I've mentioned I do? That would be my only concern with the space between the plexi and the box.

 

[Sudz_Makenzie]

Biggest I've done is a 2000 ml starter. Initially, I had the plexiglass mounted flush and the weight caused the plexi to barely brush the magnet on the fan. That's when I added the O ring and nut spacer. A couple things you can do if yours touches ... 1. Use thicker plexiglass.
2. Use four additional spacers (nuts or scrap pieces of plexi) placed between the existing spacers on each corner.
Hope this helps. Cheers

 

[rekoob]

Looks good.