Building a Stir Plate

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Building a Stir Plate

Postby twitt on Sat Jan 31, 2009 8:41 am

After reading through responses to my post on NB forum on "How much is too much yeast?" : http://forum.northernbrewer.com/viewtop ... =1&t=70145 I decided to harvest only a small sample of yeast from my yeast cakes from now on and make a starter using a stir plate.
"To alcohol: The cause of, and solution to, all of life's problems." - Homer J. Simpson
Primary: Garbage Pail Ale (literally)
Secondary: n/a
Bottled: Broad River Amber, Magnum Amber, Kolsch, Witt's Winter Ale, Sofa King Hoppy (Double IPA)


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Re: Building a Stir Plate

Postby twitt on Tue Feb 10, 2009 6:17 pm

The photos below show the build process. The entire project could have cost less than $10, but I "splurged" on a project box for $5.99 from Radio Shack.
Attachments
1.JPG
Here's a 4GB hard drive I had laying around... any desktop hard-drive will do though. Desktop hard drives contain rare earth magnets (neodymium) that can easily be harvested for a project like this.
1.JPG (26.57 KiB) Viewed 4015 times
2.JPG
Remove the cover.
3.JPG
Remove the upper magnet (in this case secured by two screws on either side). In this photo, the magnet is crescent-shaped and fixed to a steel bracket.
4.JPG
Next, remove the hard drive heads by sliding them off the actual hard drive plates. Then remove the lower bracket and magnet.
5.JPG
Warning! The magnets are very fragile. Trying to remove the directly with force may break them. Rather, bend the steel bracket away from the magnet like this.
6.JPG
Next item is a PC fan. Any should do. In this case, I had a deal Dell power supply laying around.
7.JPG
Next item is a power supply. This is a 9-Volt DC power supply from a PC Speaker system I don't use anymore.
8.JPG
This is a project box, rocker switch, and a 3 watt, 25-Ohm potentiometer, and knob from Radio Shack (total < $15)
9.JPG
Now to remove the fan from the power supply...
10.JPG
Done...
11.JPG
Close ups of the rocker switch, and a 3 watt, 25-Ohm potentiometer, and knob
12.JPG
Most of the items are ready here...
13.JPG
Here I drilled the holes and mounted the rocker switch and potentiometer, then drilled a hole and installed a grommet for the power supply cord.
14.JPG
Front view (upside-down) view of stir plate...
15.JPG
I then used a 1" o-ring to space the magnet from the fan. When I initially turned it on, the magnet was so straong, the fan would barely turn. Spacing the magnet from the fan allows the fan to operate at a nearly normal speed.
16.JPG
Then I drilled four holes in the top of the stir plate to mount the fan underneath.
17.JPG
I then used 1" aluminum spacers to distance the fan from the underside of the top of the stir plate. If you don't do this, the magnet will rub and prevent the fan from spinning.
18.JPG
Mounting complete...
19.JPG
Wiring taped down to prevent it from being drawn into the fan.
20.JPG
Complete!
"To alcohol: The cause of, and solution to, all of life's problems." - Homer J. Simpson
Primary: Garbage Pail Ale (literally)
Secondary: n/a
Bottled: Broad River Amber, Magnum Amber, Kolsch, Witt's Winter Ale, Sofa King Hoppy (Double IPA)


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Re: Building a Stir Plate

Postby twitt on Tue Feb 10, 2009 7:01 pm

After this complete I tested it using a paper clip.

"To alcohol: The cause of, and solution to, all of life's problems." - Homer J. Simpson
Primary: Garbage Pail Ale (literally)
Secondary: n/a
Bottled: Broad River Amber, Magnum Amber, Kolsch, Witt's Winter Ale, Sofa King Hoppy (Double IPA)


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twitt
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Posts: 217
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Re: Building a Stir Plate

Postby twitt on Wed Feb 11, 2009 8:58 pm

OK, two updates. First, the 1" aluminum spacers may have been too far from the surface. So I replaced them with grommets I had laying around (they're probably about 1/4 inch. Second, the 9 volt power supply I was using spun the fan way too fast for the stir bar. I replaced the 9 volt supply with a 5 volt dc supply that I had laying around from a Motorola RAZR phone.
Attachments
DSC07811.JPG
Notice the 1" aluminum spacers have been replaced by the 1/4 inch black grommets.
DSC07811.JPG (30.88 KiB) Viewed 3868 times
"To alcohol: The cause of, and solution to, all of life's problems." - Homer J. Simpson
Primary: Garbage Pail Ale (literally)
Secondary: n/a
Bottled: Broad River Amber, Magnum Amber, Kolsch, Witt's Winter Ale, Sofa King Hoppy (Double IPA)


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twitt
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Posts: 217
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Re: Building a Stir Plate

Postby twitt on Wed Feb 11, 2009 8:59 pm

I put everything back together and tested with the flask and stir bar that arrived today from Northern Brewer.

"To alcohol: The cause of, and solution to, all of life's problems." - Homer J. Simpson
Primary: Garbage Pail Ale (literally)
Secondary: n/a
Bottled: Broad River Amber, Magnum Amber, Kolsch, Witt's Winter Ale, Sofa King Hoppy (Double IPA)


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twitt
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Posts: 217
Joined: Fri Dec 05, 2008 9:56 pm

Re: Building a Stir Plate

Postby sootedpair on Mon Apr 06, 2009 5:53 pm

I'm a complete moron when it comes to stuff like wiring a thing like this. It looks like I have the same rocker switch and pot as you're using, so can you give me a run down of what wires go to what please?

TIA,
Scott


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Re: Building a Stir Plate

Postby twitt on Mon Apr 06, 2009 8:57 pm

Hi Scott, hope this helps:
Step 1: Connect the positive wire (red) from the power supply directly to the fan’s positive (red) wire
Step 2: Connect the negative wire (black) from the power supply to the middle terminal on the rocker switch
Step 3: Using a small wire (about 4 inches), connect one of the outer terminals on the rocker switch to the middle terminal on the potentiometer
Step 4: Connect the fan’s negative wire (black) to one of the outer terminals on the potentiometer switch
Step 5: Make yeast and drink beer.
Attachments
Stir Plate Wiring Detail.PNG
Stir Plate Wiring Detail.PNG (915.97 KiB) Viewed 2881 times
"To alcohol: The cause of, and solution to, all of life's problems." - Homer J. Simpson
Primary: Garbage Pail Ale (literally)
Secondary: n/a
Bottled: Broad River Amber, Magnum Amber, Kolsch, Witt's Winter Ale, Sofa King Hoppy (Double IPA)


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twitt
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Posts: 217
Joined: Fri Dec 05, 2008 9:56 pm

Re: Building a Stir Plate

Postby backyard brewer on Thu May 14, 2009 10:35 pm

that's one of the most comprehensive write-ups I've seen Twitt! Nice work!

For those of you that don't feel like flagging down all the parts or want the improved performance of a voltage regulator driven stir plate I finally released this kit:
Image

It runs $14.95 plus shipping and includes almost everything you need but a fan, drive magnet, case and stir bar.


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Re: Building a Stir Plate

Postby twitt on Wed May 27, 2009 9:53 pm

After some minor tweaks to the magnet placement on my fan (thanks to this article: http://www.madzymurgists.org/stirplate.cfm and the photo below) I was able to place the magnet in such a way that it doesn't cause the stir bar to wobble at all. I was then able to upgrade my power supply to a 9v and get great results. I can get my 1000ml flask to vortex straight to the bottom. Will post video soon...
Attachments
magnet placement.JPG
magnet placement.JPG (29.3 KiB) Viewed 2536 times
"To alcohol: The cause of, and solution to, all of life's problems." - Homer J. Simpson
Primary: Garbage Pail Ale (literally)
Secondary: n/a
Bottled: Broad River Amber, Magnum Amber, Kolsch, Witt's Winter Ale, Sofa King Hoppy (Double IPA)


User avatar
twitt
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Posts: 217
Joined: Fri Dec 05, 2008 9:56 pm

Re: Building a Stir Plate

Postby twitt on Thu May 28, 2009 7:25 pm

Updated video:
"To alcohol: The cause of, and solution to, all of life's problems." - Homer J. Simpson
Primary: Garbage Pail Ale (literally)
Secondary: n/a
Bottled: Broad River Amber, Magnum Amber, Kolsch, Witt's Winter Ale, Sofa King Hoppy (Double IPA)


User avatar
twitt
Site Admin
 
Posts: 217
Joined: Fri Dec 05, 2008 9:56 pm

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