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

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I gave up entirely on using the hard drive magnets. Far too much hassle to remove them from the HD and also too much hassle trying to position them properly. I now use store bought rare earth magnets. They are not at all expensive and they are much easier to position for more precise balance. The magnets cost about $2.00 each including shipping. I like the 1/4" x 1" size and I mount them vertically. I've built quite a few stir plates for my brewing friends and they're all working quite well.
 
i may have missed it, but is it possible to use a smaller computer fan? A buddy gave me two fans that are smaller than the ones i've seen people using here and i'm curious if they will work for this project. I'm not one that makes huge starters and just want something that will help along the process.
 
Donner said:
i may have missed it, but is it possible to use a smaller computer fan? A buddy gave me two fans that are smaller than the ones i've seen people using here and i'm curious if they will work for this project. I'm not one that makes huge starters and just want something that will help along the process.
Click to expand...

You might be able to use a smaller fan. But it will be putting the same load on a smaller motor so it might not last as long and you will probably need a very small stir bar unless you put a plate on top of the fan to spread out the magnets.
 
What size stir bars does everyone use? I got a couple of 2" bars for a 1000L flask and it just wont hold the bar and keeps throwing it off the center. Is the bar maybe to big? Also has everyone had better luck with the pivot rings or without?
 
For stirbar size I think people have had the best success with something no bigger than your magnet itself. I'm using a 1.5" with a hard drive magnet and it works well.
 
I just wanted to say thanks for doing this thread with such great instructions and photos. My 14 year old boy just finished this last night. He is going to use it in his electricty project for 4-H, and then I get it for my use. We spent Sunday afternoon building it, and then a couple of hours last night getting the magnet placement and proper spacing set correctly. We are getting a full vortex with the bubbles just touching the bottom of a full 1 liter flask. I can't wait to the see the judge's face when he tells him what this will be used for. :) I am making sure he knows that these stir plates have labortory uses also. I will update after it gets judged. He is putting together a cost sheet today and I am intrested in seeing the final total.

Thanks again,
 
Thanks for the build notes. I soldered mine up yesterday. Spins the fan great!

I used a 9v power supply I found for an old piece of hardware and a 120mm case fan I had wasting space. But I have yet to glue my washer on. Namely because I haven't gotten my flask or stir bar yet so I'll just wait to test it.

I am planning on super gluing the washer on. To align it I have turned the fan on and used a pencil to inscribe circles that SHOULD be equidistant from the center. So hopefully I'll just line up the inner circle of the washer with one my my circles and have to do minimal adjustment while gluing it up.

Here are some pictures of my proposed method of alignment for the washer as well as the HDD magnets I am planning to use. I also noticed my hdd magnets came as 4, not as one bar. So hopefully this system with them spread out will work?





Thanks again for the thread. Good stuff.
 
json2001,
looks good - I actually broke my 1-piece hard drive magnet in half and re-glued it (epoxy) to my fan much like yours looks. Spin bar stays put much better. So, you set up should be fine.
These Flasks are great, love the cork coating for sure grip and cool right off the burner.
 
Hang Glider said:
json2001,
looks good - I actually broke my 1-piece hard drive magnet in half and re-glued it (epoxy) to my fan much like yours looks. Spin bar stays put much better. So, you set up should be fine.
These Flasks are great, love the cork coating for sure grip and cool right off the burner.
Click to expand...

Oh very cool. I'm going to be ordering some ingredients and some other odds and ends from AHS soon. So I was considering just getting their yeast starter kit. Seems like I should get the 2L flask?

Thanks for the feedback!
 
I just built one yesterday using a three inch fan from an old computer, the magnets from the HD, and the items listed in the first post. Used an old phone charger (6V) for power source. waiting for my flask and stirbar, but tried the plate out with a glass of water and one of the HD magnets, with not much luck.

I am totally new to building, and quickly slapped this together. The magnet jumps around in the glass, the stirplate rattles around a lot, and the vortex does not exist.

was thinking about putting both magnets on the washer on the fan, though i don't understand what everyone means by spacing them, and balancing the weight of the two magnets with smaller washers to prevent the rattling. Does that make sense/sound right?

By the way, thanks for a truly amazing and helpful thread,

cheers
 
avibayer - waiting for flask and stirbar -
while many types of magnets exist for the underside with the fan, I don't think you'll be able to test it without a stirbar - that plastic casing is somewhat essential in getting things to spin. As far as the spacing - two meanings exist - 1) look at post 287 - spaced apart, and 2) height off the fan motor. Some of the stronger magnets interfere with the motor spinning (it's essentially a type of electromagnet in itself), so raising the magnet away from the hub of the motor often helps. Good luck, I think you'll probably be pleased when your stirbar arrives.
 
I'm building my second one. The first worked out so well, that I'm building one for a friend. I got lots of HDD magnets and a few old printer selection boxes that are obsolete now that network print servers come in every printer sold.

I find the HDD magnets work very well, and even though I can pull a vortex down to nearly the bottom with a 1" stirbar, I never run it that fast. I just turn it on low and let the thing keep the yeast mixed up.

The results have been just as good as cranking it.
 
So think I've got mine wired up right, however it doesn't seem like the fan has much variability at all through the rheostat. The only way I can tell is to tape the magnet to the fan and listen to frequency of the vibrations it causes in the case. It seems a bit faster with the rheostat dialed all the up vs all the way down, but it's not much at all.

I saw elsewhere in the thread that some people were using a resistor. Would doing so help my problem? Any particular rating (or whatever you call it) to use?

Unfortunately I don't have my stir bar so I can't see how well this current setup will work.
 
stir bar came, and after playing with the magnets for an hour, i was able to get a vortex down to the bottom. my yeast were super happy. I used a washer with a hole in the middle that was so big, the HD magnets wouldn't rest across the middle. So i glued a piece of metal across the gap, put the two HD magnets on it, and it did the trick.

the only issue i have, is i have to make sure the stir bar is in the middle of the flask to get it to spin properly, and with murky starters that can be tricky. but its kinda fun too. finding the sweet spot.

thanks for an awesome thread, helping non-engineers like me build a stir plate on the cheap.
cheers
 
Well, I'm back from a long tournament Bass fishing season. I'm glad to see my thread has continued to stay on the first page... 30 pages!?!?
 
In case anyone cares, 64-3134 is not the right part numbers for quick disconnects that fit that rocker switch. So you don't have to make another trip like I did, get 64-4040's. You need 1/4" disconnects for the rocker switch.

In other news, I have a 120mm pc fan in mine, which I cut all the blades off with a dremel, and it doesn't seem like it spins fast enough to make a vortex to the bottom. Do I need to use both of the HD magnets? I can't tell if I can't get a vortex to the bottom because the fan speed isn't fast enough, or I don't have enough magnet force.
 
quixand said:
In case anyone cares, 64-3134 is not the right part numbers for quick disconnects that fit that rocker switch. So you don't have to make another trip like I did, get 64-4040's. You need 1/4" disconnects for the rocker switch.
Click to expand...

Unless they have changed the design of the rocker switch, the 3/16 disconnects should work. I built 3 stirplates for club members following my own "how to thread" to make sure I didn't miss anything or mess up the instructions. I'll take a run down to the SHACK today and take a look at what they are stocking. 3/16" vs. 1/4" disconnects shouldn't make much of a difference, however I will verify and edit the thread for now.

Thanks for the input!
 
Anthony_Lopez said:
Unless they have changed the design of the rocker switch, the 3/16 disconnects should work. I built 3 stirplates for club members following my own "how to thread" to make sure I didn't miss anything or mess up the instructions. I'll take a run down to the SHACK today and take a look at what they are stocking. 3/16" vs. 1/4" disconnects shouldn't make much of a difference, however I will verify and edit the thread for now.

Thanks for the input!
Click to expand...

Well...I can most assuredly tell you the part number of the quick disconnects wouldn't even come close to fitting the part number for that rocker switch.

When I went back later that evening, the part number I picked up was snug, but a perfect fit. Not sure if I got an older switch with the same part number before they went to a smaller size or what...but just wanted people to know to double check at the very least. There may be multiple sizes of the rocker switch part number, with different sized male ends. LOL
 
quixand said:
Well...I can most assuredly tell you the part number of the quick disconnects wouldn't even come close to fitting the part number for that rocker switch.

When I went back later that evening, the part number I picked up was snug, but a perfect fit. Not sure if I got an older switch with the same part number before they went to a smaller size or what...but just wanted people to know to double check at the very least. There may be multiple sizes of the rocker switch part number, with different sized male ends. LOL
Click to expand...

I had the same issue so I returned the qds and got a soldering iron
 
Ok I apologize if this was explained earlier, but I am having trouble comprehending the theory behind this.

How does this thing work? Does the top of this thing actually move or the fluid move due to the magnetic field generated by the magnet/washer on the fan?

See us Social Science nerds didn't have many labs :)

Thanks!
 
k2brew said:
Ok I apologize if this was explained earlier, but I am having trouble comprehending the theory behind this.

How does this thing work? Does the top of this thing actually move or the fluid move due to the magnetic field generated by the magnet/washer on the fan?

See us Social Science nerds didn't have many labs :)

Thanks!
Click to expand...

A magnetic stir bar goes inside the flask and when the fan with the magnets spins it spins the stir bar.
 
Ohhh.... drrr

It's never good to be the one in the room wearing a helmet and drooling. Unless of course you have just had a couple litres of Apfelwein :mug:

Thanks, now I have another project in addition to going AG, Kegging and building a fermentation chamber.
 
Getting the right amount of spin from your fan, the right amount of pull from magnets, then arranging them properly to spin the bar perfect...are certainly a test of your resolve. LOL

Talk about frustrating.
 
Hey, just wanted to say thanks for the great write-up . I finished this up tonight and it works as advertised.
 
quixand said:
Getting the right amount of spin from your fan, the right amount of pull from magnets, then arranging them properly to spin the bar perfect...are certainly a test of your resolve. LOL

Talk about frustrating.
Click to expand...

That's the point of having the potentiometer and the steel washer. They allow you to adjust your fan speed as well as your magnet locations. With a little bit of tweaking, I assure you - you will get it.

On another note, who is this guy selling stir plates on HBT Banners up top? They look an awful lot like the ones we have been building here.
 
Anthony_Lopez said:
On another note, who is this guy selling stir plates on HBT Banners up top? They look an awful lot like the ones we have been building here.
Click to expand...

He's Dan Jeska from Michigan. His stir plate design is unique and appears to be superior in that it uses an LM317 voltage regulator along with a pot for better speed control. He also uses rare earth button magents instead of the salvaged hard drive magnets. The price is very good at only $42 including shipping and a stir bar. Lifetime warranty too.

http://www.stirstarters.com/

He also has instructions with a parts list in case you want to build your own based on his design. I don't have one of his units, but it appears to be a sound design. I built a couple for myself (and about fifteen more for my friends) using a 110v muffin fan and a light dimmer for speed control. Simple and effective with a minimum of components. My cost using new parts is roughly the same as his price of $42 although I'm using a larger stir bar and stronger magnets than he lists for his.
 
Anthony_Lopez said:
On another note, who is this guy selling stir plates on HBT Banners up top? They look an awful lot like the ones we have been building here.
Click to expand...

To be fair, this design has been around for quite some time.
Your stir plates are very close to mine.. I built my stir plate based off plans out on the web, and other stir plates seen here, in mid 2007.
 
capcrnch said:
To be fair, this design has been around for quite some time.
Your stir plates are very close to mine.. I built my stir plate based off plans out on the web, and other stir plates seen here, in mid 2007.
Click to expand...

Yes, the muffin fan stir plate design has been around for at least 10 years. Here you can find a post from early 1999 on the HBD:

http://hbd.org/hbd/archive/2954.html#2954-6

I've often wondered who came up with the original. We may never know.
 
I wasn't claiming that he copied me. What I believe I said was that someone is selling the stir plates WE have been building on HBT for a long time.
 
Thanks to the OP for the great instructions!

I have my first "stirplated" yeast starter spinning away in the basement, bound for a Belgian Dubbel this weekend. This was a fun build.

The metal washer was great advice, as I had to fiddle with the magnet placement quite a bit to get my 50mm stir bar to work. Actually, I never glued the magnets on; they seem to sit there fine under their own power. I may try to get fancy and add some additional resistance to the circuit. I can only turn the potentiometer up about 30% before I throw the bar and at the lowest setting, I get a vortex all the way to the bottom.
 
Tripod said:
That is good for saving a buck. But there's just something more satisfying to the DIYer about building your own. Whether I could've done it for cheaper really isn't the issue for me...

-Tripod
Click to expand...
I agree but if can save money, time, and get a better product well....
I have actually been looking for a good deal on a combo hot plate / stir plate so I can do the whole thing in the basement.
 
Tripod said:
That is good for saving a buck. But there's just something more satisfying to the DIYer about building your own. Whether I could've done it for cheaper really isn't the issue for me...

-Tripod
Click to expand...

Exactly. Don't forget who you're talking to. If we wanted to just go out and buy something WTF would we be spending six hours on a weekend making two cases of beer?

Edit: But seriously, thanks for the link. At some point I'd like to get more into yeast culturing and they have some cool stuff on there.
 

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