My Stirplate... Cheap and Easy Build...

Just finished my own stirplate, wanted to show what worked for me.

I decided not to use a potentiometer, and just have a single setting for my vortex. I used a 12 volt computer fan, just like everybody else. I used 2 7lb magnets from American Science and surplus. Picked up a black case and switch there. I ended up using an old lcd tv transformer and a 50 ohm 5 watt resistor I had laying around. To get the magnets away from the fan and up to the level of the outer box, I was fortunate enough to borrow the laser cutter at school and build some rings out of acrylic to mount the magnets into, it looked a lot nicer before the JB weld. JMilton1987 helped me out with the CAD files for the cutter. Also, the bar I'm using is a 2" bar.







I like the set up because it breaks down nicely and stores everything in the case.

thanks for the great directions. just finished making my stirplate by following your directions it works!! had to buy an old fan and magnet from the computer shop for 15bucks. after all parts still only 43bucks

Very nice! Glad to see people are still using this thread

what did you use for a stirbar? i tested my stir plate with a small screw it spun for a while then it stoped. would a comercial stir bar spin better?

Most folks are buying stir bars I believe. They will work better then a screw... I wonder though if you could use just a 2" piece of 1/4" stainless rod..

Well I got mine kicking. I had negligible success with power supplies left around the house. I seem to have lost some. So I had to go back a 12v and throw a resistor between the power and fan motor. It provides a little more juice than I wanted but the computer store down the street has a basket of used supplies for $10 but for some reason the 12v 500mA was $40 I asked about it and the guy at the desk was some dork that had no idea.

Anyhow I went with a two inch bar and have four magnets on each side to hold the bar. The magnets I got from harbor freight tools. All I have to do is solder everything up (only assembled with gator clips right now) and close up the box. I'll probably start using it tonight so I can get get a starter going for my Pliney clone from AHS that I'll brew on Monday.

5L flask on my stirplate that I made with a power strip that a computer monitor would sit on.



1.5L step up starter in my 3L flask. The power strip is still fully operational. I need to permanently mount my pot somewhere on the box.

payton34 said:

what did you use for a stirbar? i tested my stir plate with a small screw it spun for a while then it stoped. would a comercial stir bar spin better?

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Yes. Far better.

RegionalChaos said:

Most folks are buying stir bars I believe. They will work better then a screw... I wonder though if you could use just a 2" piece of 1/4" stainless rod..

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You would want to use either 304 or 316 stainless, but the problem is that neither is magnetic.

MatterOne said:

You would want to use either 304 or 316 stainless, but the problem is that neither is magnetic.

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SS won't work as it's not ferrous and cannot be magnetized AFAIK. I think there are some types of SS that are somewhat magnetic, but only weakly so. Stir bars have a magnet embedded withing a Teflon casing. The magnet inside the stir bar magnetically couples with the stir plate spinning magnets. Store bought stir bars are relatively inexpensive and available in a wide variety of sizes and configurations. IMO, not worth the time and effort to make DIY stir bars. It's important to get a stir bar that matches the spacing on the stir plate magnets closely for optimum performance.

so i've been at it for 2 hours, and i can't for the life of me get the stir bar to stay on the bottom of my growler. i've tried all sorts of magnet configurations, hard drive magnets, harbor freight magnets. spaced off the fan center, directly on the fan center. nothing seems to work.

any suggestions?

slakwhere said:

so i've been at it for 2 hours, and i can't for the life of me get the stir bar to stay on the bottom of my growler. i've tried all sorts of magnet configurations, hard drive magnets, harbor freight magnets. spaced off the fan center, directly on the fan center. nothing seems to work.

any suggestions?

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Get a flask.

Get a 1/2" stir bar.

mthompson said:

The potentiometer won't turn the supply all the way off. If you want a slower speed, you could piggy back a second behind it.

Later,

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are you able to run POTS in series? i asked a few ppl i'm friends with that had formal electronics schooling and they didn't know for sure or were playing dumb.

i haven't stirred a plate yet but the POT doesn't seem to have a wide rpm range control imo but again i haven't run it in a real world ap. yet. i'm waiting to go and get some stand off screws tomorrow to complete the build and test the functionality.

i built mine per specs of the original post except i was only able to scronge a 2" or so computer fan not a standard 4"....


side note: radio shack employee aren't that bright. also the first rocker switch i bought was bot of box failure but i soldered it and didn't check continuity between power and load prior to soldering... opps

Yes, you can run potentiometers in series. Your friends were either playing dumb or they paid no attention what so ever in their "electronics schooling", as it's pretty basic.

Scimmia said:

Yes, you can run potentiometers in series. Your friends were either playing dumb or they paid no attention what so ever in their "electronics schooling", as it's pretty basic.

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thanks, good to know

Catt22 said:

SS won't work as it's not ferrous and cannot be magnetized AFAIK. I think there are some types of SS that are somewhat magnetic, but only weakly so.

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That's basically what I said.

What I was getting at was that although there are grades of SS that ARE magnetic, either of the two types you would want to use, unfortunately, are not.

MatterOne said:

That's basically what I said.

What I was getting at was that although there are grades of SS that ARE magnetic, either of the two types you would want to use, unfortunately, are not.

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My main point was that a DIY stir bar doesn't make much sense as the manufactured ones are inexpensive and readily available off the shelf.

So, I followed the original thread exactly (at least, as far as I can tell), but I'm unable to get my fan to spin at all.

I'm using all the exact parts from the OP, a 5v Motorola wall wart, and an 80mm fan. The wall wart has two black wires, one with a dashed white line - I took the wire with the line to be positive, and the flat black to be negative. The fan has red and blue wires, so I assumed the blue to be negative.

Any idea how I can troubleshoot this? I'm not much of an electrician...

Shag said:

So, I followed the original thread exactly (at least, as far as I can tell), but I'm unable to get my fan to spin at all.

I'm using all the exact parts from the OP, a 5v Motorola wall wart, and an 80mm fan. The wall wart has two black wires, one with a dashed white line - I took the wire with the line to be positive, and the flat black to be negative. The fan has red and blue wires, so I assumed the blue to be negative.

Any idea how I can troubleshoot this? I'm not much of an electrician...

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The fan should have a rating on it. I.e, voltage and current. What does it say exactly? Same for the wallwart. Try reversing the wires (briefly!).

passedpawn said:

The fan should have a rating on it. I.e, voltage and current. What does it say exactly? Same for the wallwart. Try reversing the wires (briefly!).

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It's a 12VDC fan, 1.9W, .16A. I reversed the wires from the wall wart, which fired the fan right up. I guess I should have tried that. Thanks!

Doesn't seem to spin all that fast, but then again, I don't really know how fast it should spin. Won't spin at all with a magnet directly attached, so will have to add some shielding, looks like. Once I get a stir bar, I'll have to figure out if I have enough juice...

Thanks to the OP for the plans!

You might need more than 5v. I started with a 6v power supply and couldn't get much with my 2" bar magnet. So I ran to the store down the street that has a basket of used supplies for $5-$10 and got a 12v 1amp model and just put a resistor in line from the power supply to the potentiometer.

I used the instructions from this thread to make my stirplate....worked out great.I took an old computer ...robbed the power supply from it, the power switch and the hard drive.Used the power supply and fan for the project box (just had to remove all the un-necessary guts and cut out an opening in the top for the fan.Robbed the magnet from the hard drive....Heck the only things I had to buy were the potentiometer, the knob , and the stirbar for a grand total of 14 bucks.I used an old 12v powers supply from a rechargeable flashlight.Once I got the magnets situated right it worked at full speed with a 1 gallon growler that has a concave bottom.:rockin:Thanks to the op and all the fine folks who contributed to this

Just test fired mine this morning! Woo Hoo! :rockin:

Hey all. I just completed my stirplate build, and I thought I would stop by to share. here's a brief video of it in action (test run, with water):

[ame="http://vimeo.com/10250447"]Homebrew DIY Stirplate on Vimeo[/ame]

I'm hoping to get it fired up with an actual starter this weekend.

Many thanks to Anthony_Lopez for the detailed instructions! rock on.

Im trying to build a plate to use a 2 inch stir bar for a 4 liter flask. Do any of you guys think one of these would work well
http://www.kjmagnetics.com/proddetail.asp?prod=BY042
or
http://www.kjmagnetics.com/proddetail.asp?prod=BY084

lowlife said:

Im trying to build a plate to use a 2 inch stir bar for a 4 liter flask. Do any of you guys think one of these would work well
http://www.kjmagnetics.com/proddetail.asp?prod=BY042
or
http://www.kjmagnetics.com/proddetail.asp?prod=BY084

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Can't answer that exact Q, but I use a 2" stir bar in a 4L flask. I have two stacks of magnets spaced about 2" apart. One stack is flipped to get opposite polarity. The magnets are the little round rare earth ones that are 1/2" diameter by 1/16" thick. I hold everthing together with hotglue. I posted some pics here.

Your big magnet might work fine, too.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=67488

You can order those online or if you have a store nearby. I used them with a 2" stirbar and I stacked I think 3 or 4 on the fan with a spacer. It works very well and they were cheap. I have two left over holding things on the fridge.

I just made my own version of this. Seems to work great on my test sample. I put up my how-to with pictures and video up on my blog:
http://stubborndog.wordpress.com/2010/05/09/diy-magnetic-stir-plate/

Just renewed my subscription, glad to see this is still going. Keep up the good work guys!

darkfrog13 said:

I just made my own version of this. Seems to work great on my test sample. I put up my how-to with pictures and video up on my blog:
http://stubborndog.wordpress.com/2010/05/09/diy-magnetic-stir-plate/

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Not bad. I'd be a bit concerned about the suitability of the materials for your homemade stir bar. I'm not sure that the wire insulation or hot glue are food safe. If you were just doing it to test with water that's fine but I would either think about getting a real stir bar or finding a better suited coating (food safe) for the homemade one.

Just got my stir bar in the mail from Scientific Equipment of Houston. Tested the stir plate, after a couple of tries to get the bar from throwing, it worked great.



I had an aquarium fan I use to use to cool my stereo cabinet, but after changing to an open air cabinet, I no longer used it. A coworker dropped his external hard drive, and gave me the broken case (the circuit board was messed up, the plastic case was fine) I moved the rubber pads from the side to the new bottom of the case, and added felt pads to the top and sides of the fan, as well as washer, and magnet from an old broken hard drive.

It stayed very stable, although a little noisy from the stir bar spinning. After letting it run for an hour, it didn't throw the bar.

I read this thread, and decided I can build a stirplate! Easy right. HA!
I already have an old hard drive for the magnets, and several 12 volt wall chargers, all i need is a fan. So I asked my IT guy at work for a 12 volt fan, and he gladly obliged. Got it home and went to wire it up, and I got 4 black wires (see pic). Now I'm not a retard, nor am super proficient with electrical, but every fan pic I see online, has red and black wires... Most of the pics on this thread have red and black wires... so why would I get the one with 4 black wires. I'm assuming I have a positive, a ground a control and something else... anyone have any clue which is which, or should I just scrap it and get another fan.

I striped back the wires on an old cell phone charger, and did the test meter touch and go on every terminal on the 4 pin connector, and nothing.

With 4 wires the hot and neg will be paired. They should be on the outside as in +-xx or xx+-. At least, being in IT myself that has been my experience.

sprocketmaker said:

I read this thread, and decided I can build a stirplate! Easy right. HA!
I already have an old hard drive for the magnets, and several 12 volt wall chargers, all i need is a fan. So I asked my IT guy at work for a 12 volt fan, and he gladly obliged. Got it home and went to wire it up, and I got 4 black wires (see pic). Now I'm not a retard, nor am super proficient with electrical, but every fan pic I see online, has red and black wires... Most of the pics on this thread have red and black wires... so why would I get the one with 4 black wires. I'm assuming I have a positive, a ground a control and something else... anyone have any clue which is which, or should I just scrap it and get another fan.

I striped back the wires on an old cell phone charger, and did the test meter touch and go on every terminal on the 4 pin connector, and nothing.

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Cut the plug off and try adding power to the wires. If single wires don't work pair them up like mentioned and you might end up digging where there's taters.

NoNothing said:

With 4 wires the hot and neg will be paired. They should be on the outside as in +-xx or xx+-. At least, being in IT myself that has been my experience.

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Thanks for the responses... I just found this Pin Out Diagram, which seems to confirm your advise, so I'll give it another try tonight.

Cheers!

sprocketmaker said:

Thanks for the responses... I just found this Pin Out Diagram, which seems to confirm your advise, so I'll give it another try tonight.

Cheers!

Click to expand...

NP, its what I do, hope your fan is the same as the 'standard'.

Your fan looks like a OEM and could be anything but likely will follow the diagram you found. You should get full speed by putting 12v across pins/wires 1 and 2.

You may have to short 4 and 2 but usually it's open for full speed.
Good luck.

HELL YESSSSSSSS!!!!! Another one lives!!! My brand new baby is happily stirring the crap out of 750ml of water as I type. This calls for a beer! God I'm f'ing giddy..give me some bottle conditioned beer to start some yeast from...oh wait, maybe i'll finish that mostly-full growler of Schlafly's awesome limited release draft-only Burn Ward wheat [a hoppy American wheat] and kill 2 birds with one stone :rockin::rockin:

Finally got mine done, thanks for the inspiration Anthony!

https://www.homebrewtalk.com/f51/my...ir-plate-build-nearly-no-tools-needed-186481/

Question about the initial circuit design - should pin 1 (the furthest left pin in the picture) of the potentiometer be connected to ground or coupled with the output pin (middle/pin 2)? It appears that in this design it's not connected to anything.