DIY Stirplate - Could this get any easier?

This was one of the easier and more fun projects that I've completed.

I got the project box, a switch, potentiometer, and a female power plug from Radio Shack and the rest scavenged from around the house.

Parts List

Project Enclosure (8x6x3")
25-Ohm 3-Watt Rheostat
Rocker Switch
Fan from Computer Power Supply
Magnet from Hard Drive
Stainless Steel Washer (don't know size)
9V Power Plug from old cell phone
4 Screws, 8 nuts, 4 nylon spacers, and some washers
Some wire (~ 2 ft)

I drilled up the project box for the power plug, switch, and rheostat, then soldered everything up as shown in the pictures below.

I had 4 machine screws and some matching washers and nuts lying around the garage. I had to slightly drill out the holes in the fan for these to pass through.

I used the stainless steel washer as a spacer to keep the magnet off the fan. You have to use a non-magnet spacer here otherwise the magnet will interfere with the fan. I attached the washer to the fan with industrial velcro and the washer is glued to the magnet. This allowed me to adjust how the magnet/washer sat on the fan to better center it. If its not centered well, you the stir bar is more easily thrown.

I have a 2" stir bar that I want to trade out for a slightly smaller one.

In my experience, the hard drive magnets will throw a 2" bar. I built a couple of these types of stir plates, and each time I stacked 3 magnets. It would spin a ½" bar great, but not the 2".

If you really want to spin that 2" bar, try two sets of magnets, spaced apart. One of the piles needs to be inverted to get the opposite pole facing up. I did this and it works great.

See this post for pic.

Very informative thread. I have seen these DIY builds on here before and was always planning on someday building a stirplate, but never got around to it.

After seeing this and also having to deal with a nagging SWMBO about the spilt wort on the tile counter due to me shaking a mason jar a little too furiously, I am definitely going to build this.

Cheers!

Sorry to hijaak your thread... here's how the magnets look in order to spin a 2" bar. Remember to reverse polarity on one of the piles! (circular metal plate was cut from a coffee can with tin snips and hot-glued to fan... makes mounting magnets a breeze).

i have used my 2" without issue for days. I do have to center it perfectly. it usually takes me 2 to 3 tries to get it right. I will be getting a 1" eventually, but the 2" is working, so why fix whats not broken.

Just to let you know, the rheostat you are looking for is a 25 ohm rheostat, not 5. I spent like 5 minutes in radioshack looking for a 5 ohm one. I guess I could have been less lazy and clicked the link.

kpr121 said:

Just to let you know, the rheostat you are looking for is a 25 ohm rheostat, not 5. I spent like 5 minutes in radioshack looking for a 5 ohm one. I guess I could have been less lazy and clicked the link.

Click to expand...

Updated OP. Thx

Nice stir plate... looks some what familiar...

Hell yeah, i copied the heck outta you. Nice quotes by the way.

passedpawn said:

Sorry to hijaak your thread... here's how the magnets look in order to spin a 2" bar. Remember to reverse polarity on one of the piles! (circular metal plate was cut from a coffee can with tin snips and hot-glued to fan... makes mounting magnets a breeze).

Click to expand...

What size magnets did you use?

just an update...

i picked up a couple 1" stir bars (vs. the 2" bar I was using before) and these work so much better.

My control over the speed via the rheastat is much improved (im able to very the depth of the vortex well) & the its so easy to get the stir bar started and it never gets thrown. Much much improved.

Definitely building one of these this weekend. It will save me so much on DME, it will pay for itself in 3 months! Don't know why I haven't done this sooner.

I just built one of these today and ordered a 1'' stirbar and flask (should be here by monday).. I was playing with it with a 1" metal rod and the magnet kept lifting the top of the fan up and hitting to underside of the enclosure. Do you guys ever see any of that? That was just a metal rod and not a magnet, I can just imagine the adjusting i'm gonna have to do to get my space just right..