My shamelessly cheap $12 DIY stir plate

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How do you do that? If I am just using the magnet and fan I can't identify the center point because of the shape. I tried with the stir bar on the magnet but there is a little play in where the stir bar will stick so that doesn't seem reliable enough.

Real easy. Put the fan on a table surface and turn it on. If it skitters and moves itself across the table surface, the magnets are off center and need to be adjusted. Just keep moving them little by little until you find a sweetspot (centerpoint). It'll take you a couple of tries, but once you feel comfortable mix up that JB Weld and lock them in place. Believe me, if the magnets are close to being centered, the stirbar will fall inline and not misbehave (as much ;))
 
Just wanted to pass it along, it may have been mentioned already though. I got this fan from NewEgg for $14.99 shipped, I didnt need anything else off Amazon so I did not qualify for the shipping, plus they are based out of my state so I have to pay sales tax with them as well.
 
fc36 said:
Real easy. Put the fan on a table surface and turn it on. If it skitters and moves itself across the table surface, the magnets are off center and need to be adjusted. Just keep moving them little by little until you find a sweetspot (centerpoint). It'll take you a couple of tries, but once you feel comfortable mix up that JB Weld and lock them in place. Believe me, if the magnets are close to being centered, the stirbar will fall inline and not misbehave (as much ;))

My fan does budge but my stir bar still gets tossed. Does that mean I need a bigger stir bar?
 
My fan does budge but my stir bar still gets tossed. Does that mean I need a bigger stir bar?

Does budge or doesn't budge? Because if it does budge that means the magnets are off center and the small 1" stirbar will get thrown all the time. I have a stirplate that is rock solid centered and I can get a ripple in my 2L flask even with the 1" stirbar, but I use a 2" stirbar for big starters and the 1" is for starters 750mLs and under.
 
fc36 said:
Does budge or doesn't budge? Because if it does budge that means the magnets are off center and the small 1" stirbar will get thrown all the time. I have a stirplate that is rock solid centered and I can get a ripple in my 2L flask even with the 1" stirbar, but I use a 2" stirbar for big starters and the 1" is for starters 750mLs and under.

Sorry does not budge.
 
Do I want the cyclone of water to touch my stir bar and send up all those bubbles? I can get it to do the cyclone but as soon a it touches the stir bar it gets tossed. Do I just need a bigger magnet?
 
Do I want the cyclone of water to touch my stir bar and send up all those bubbles? I can get it to do the cyclone but as soon a it touches the stir bar it gets tossed. Do I just need a bigger magnet?

No, the cyclone is an area of turbulence. I would fully expect that your stirbar would get tossed once the cyclone touches it regardless of the size of either the stirbar or the magnets. Reduce your speed. Also once you actually start doing starters in there, your cyclone will be less pronounced due to the higher viscosity and density of a sugar/water/yeast solution. In this case, there is a measurable quantity that tells you it's a denser liquid that brewers are directly interested in: Gravity is a measure of density.
 
I built my own stir plate, it didn't work. The first power supply I used wasn't powerful enough to spin the fan when the stir bar was present. On my second attempt, the stir bar would get tossed off immediately. I just gave up and bought a ready-made one from stirstarters.com (not spamming, check my post count - just giving a personal account). It's worked great for my 1" stir bar and 2L flask. I haven't yet tried it with my 2" stir bar and 5L flask, but that'll get to be tested when I finally make my Doppelbock later this summer.
 
We made one using the fan and a couple rare earth magnets. We glued the washer to the fan and never even had to glue the magnets down. Initially we did it for placement, but it worked so well we never messed with it. Then we mounted it into a little project box. Couldn't be happier with it!
 
Just finished mine up. Total cost less than $5.00, as the only part I couldn't find in my junk collection was a rheostat. It seems to work quite well, but I'm not sure if I'll have to put a different rheostat in, it seems to spin pretty fast even on the lowest setting. I do have a pretty nice vortex going, I'm just not sure how fast it should be going. Other than that it was a pretty fun build, and much easier than I would've expected. So glad I didn't pay $100 to buy one.

stirplate.jpg
 
I saw this exact fan on Amazon as you have posted. I also viewed the 120mm fan. I have a 2L flask coming my way and was wondering if maybe the bigger fan would be more wide and stronger for the larger flask? No worries if you cant provide a definite answer. Clean build my friend. This post is a life saver.

/w
 
ExtremeWade said:
I saw this exact fan on Amazon as you have posted. I also viewed the 120mm fan. I have a 2L flask coming my way and was wondering if maybe the bigger fan would be more wide and stronger for the larger flask? No worries if you cant provide a definite answer. Clean build my friend. This post is a life saver.

/w

I remember seeing someone saying they bought a larger fan but ended up getting a smaller one due to the rpm. Someone correct me if I'm wrong but a larger fan doesn't necessarily mean better performance. It's possible to create more drag and therefore lower rpm and less desirable results. Just my $.02
 
It's probably the power (amps * voltage) that best determines the performance, not the rpm or the diameter.
 
I already went ahead and bought the smaller one. I saw the discussions on the higher RPM. thanks for the replies gents.
 
Thanks to everyone for the awesome suggestions with this build. Here is mine! I used the smaller fan and used this magnet (since I don't have any spare hdd's).

IMG_0871.jpg
 
Thanks to everyone for the awesome suggestions with this build. Here is mine! I used the smaller fan and used this magnet (since I don't have any spare hdd's).
Nice setup. I love Ashton's and have plenty of boxes sitting around. I carved into the side for the switch. Didn't think of going through the top. I can only open the box so far because of the wire to the switch. Going through the top would probably be better.
StirPlate_zpsc0c751f4.jpg


Love this thread.
 
Nice setup. I love Ashton's and have plenty of boxes sitting around. I carved into the side for the switch. Didn't think of going through the top. I can only open the box so far because of the wire to the switch. Going through the top would probably be better.
StirPlate_zpsc0c751f4.jpg


Love this thread.

That looks awesome! Did you use a hdd magnet or another type?
 
I used a HDD magnet (I have many being in IT). One thing is that new newer larger capacity drives have a larger, stronger magnet than the older drives. I think I might have been too close to the top because of the very strong magnet. Here is a pic of a newer versus older hard drive magnet to show the size difference:
magnet_zps920720e2.jpg

The OP mentioned the front and back guards of the fan are a little different height. My first run was using the closer of the two guards. It ran ok with the real starter, but playing around I noticed it didn't spin when the magnet had a hold of it. I thought it was rubbing. I swapped out the guards for the one that is a little farther away. I have a brew coming in a couple of weeks and will try it out. Again, fantastic thread. I probably would have bitten the bullet and bought a professional one. This was cheap and a nice little project for tinkering around with. If I had a hat - it would be off to the people coming up with these ideas. Don't know how they do it! I am impressed with myself for being able to follow someone else's ideas.
 
This is how mine came out using these magnets (two of 'em) and a 1 inch stir bar. That's a two liter flask. It gets a pretty nice vortex going at full bore.

Thank you to everyone posting instructions for this!

stir.jpg
 
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Anyone have any tips on gluing the magnets? Mine keep sliding all over the place before I can get them clamped down. I guess they are resisting each other too much.
 
Nice box, looks great. I got a good deal on a 1" stir bar, $3 delivered.

http://amzn.to/148ywup

Thanks! Just an el-cheapo box from a local cigar shop. That is a good deal on the stir bar. Nice find!

Anyone have any tips on gluing the magnets? Mine keep sliding all over the place before I can get them clamped down. I guess they are resisting each other too much.

Hi 00p, I used Goop. No, seriously. It worked really well. Goop is really strong contact adhesive. You can get it at pretty much any big box store. Just apply some to both the washer and the magnets, give it two minutes or so to set up and then stick them together after that, making sure you have one magnet in one orientation and the other in the opposite (N - S).
 
Anyone have any tips on gluing the magnets? Mine keep sliding all over the place before I can get them clamped down. I guess they are resisting each other too much.


Make a spacer to go between then, something that the glue won't stick to, ( some types of plastic), or better yet, test your fan balance with the spacer installed, and glue it all on there, ( magnets and spacer).

The latter is what I did, after first gluing a thin piece of ferrous metal,( about .012-.015 thick), to the top of my fans, stick the magnets to that , ( with the spacer), and check you balance before gluing it all up.
 
Thanks to PistolsAtDawn and Stealthcruiser! I had some Goop on hand and used a toothpick as a spacer. I got everything in place, and will check it all out at lunch. You guys rock.
 
Anyone have any tips on gluing the magnets? Mine keep sliding all over the place before I can get them clamped down. I guess they are resisting each other too much.

I glued a wide penny washer to the fan with epoxy resin. Then I moved the magnets around on the washer until the balance and spacing looked right, and fixed them in place with more epoxy.
 
IMG_05861_zps5c791162.jpg


IMG_05851_zpsbd991d6b.jpg



Here's mine in work, a triple muffin fan setup removed from some equipment being scrapped at work.
The fans have a metal disc glued to the center...........This pretty much does not affect balance, ( but check any way,before you glue!).
Then, the spacers are made from plastic, with the slots cut to give the magnet some clearance, so you can re-position radially whilst dialing in the balance.
The metal disc keeps the magnets positioned, yet separated while dialing in the balance..............( positioned, yet separated.......kind of like a bra......).
When I find the sweet spot, I use some semi-runny 5 minute epoxy to secure them in place.

I would have had all 3 finished, but I busted one of the magnets crewing around with it, and have to fetch another.
 
A couple things I've learned about my stir plate build now that I've made a starter:

The thickness of the wort is sufficiently different from straight water that the 1 in stir bar gets thrown at full bore, so I had to turn the speed back a little. I set it as high as it would go while being stable.

As the yeast grew in numbers and fermentation started, it got thrown again. I'm guessing because the solution was even thicker at that point and the fluid dynamics changed. I had to reset the stir bar at a slightly lesser speed again.

The 1 in stir bar makes a good amount of noise, enough so that it's actually annoying. I'm going to try to the suggestions in this thread and see what either a piece of vinyl tubing or some old keg o-rings will do for that. Hopefully they won't increase the resistance so much that it further affects the size of the vortex I can get.

The total diameter of the magnets on my fan is just over 2 inches (two, one inch magnets), so I'm guessing that if I got a larger stir bar that might keep it from getting thrown as easily as the wort composition changes and may also help with the size of the vortex I can get.

1800 mL in a 2 liter flask is really pushing it. I have krausen foaming over the top and pushing off the foil cap. Next time I'll stick to 1500 mL or less and step it up.
 
A couple things I've learned about my stir plate build now that I've made a starter:

The thickness of the wort is sufficiently different from straight water that the 1 in stir bar gets thrown at full bore, so I had to turn the speed back a little. I set it as high as it would go while being stable.

As the yeast grew in numbers and fermentation started, it got thrown again. I'm guessing because the solution was even thicker at that point and the fluid dynamics changed. I had to reset the stir bar at a slightly lesser speed again.

The 1 in stir bar makes a good amount of noise, enough so that it's actually annoying. I'm going to try to the suggestions in this thread and see what either a piece of vinyl tubing or some old keg o-rings will do for that. Hopefully they won't increase the resistance so much that it further affects the size of the vortex I can get.

The total diameter of the magnets on my fan is just over 2 in (two, one inch magnets), so I'm guessing that if I got a larger stir bar that might keep it from getting thrown as easily as the wort composition changes and may also help with the size of the vortex I can get.

1800 mL in a 2 liter flask is really pushing it. I have krausen foaming over the top and pushing off the foil cap. Next time I'll stick to 1500 mL or less and step it up.

My findings were very similar to yours. I found that by rotating my flask and moving it around the plate very slightly, I was able to find a sweet spot where my bar didn't make a huge racket and is actually pretty quiet. I also doubled up on magnets (one on top of the other). This helped amazingly in reducing bar-throwing and noise (not sure if it was just the slight additional height or change to magnetic field that did the trick).

To combat the krausen, add 1 drop of Fermcap while boiling the wort. It'll help avoid a boil over and also keep the krausen from forming during spinning.
 
I like the simplicity of this build. I might have to give it a try.

I'm wondering, since builds like this involve attaching weight to the fan, and moving air isn't a goal, is there any reason not to clip the blades off the fan? Would it help, hurt, or just be a waste of time?
 
I'm wondering, since builds like this involve attaching weight to the fan, and moving air isn't a goal, is there any reason not to clip the blades off the fan? Would it help, hurt, or just be a waste of time?

I can't honestly see why you would need to. I'd suspect that it would throw off the balance of the motor and cause you more headaches than it'd be worth. Or without the extra resistance from the air, the motor might spin at higher RPMs than you'd want and burn out faster.

But I'm just guessing here, I really am not sure.
 
is there any reason not to clip the blades off the fan?

I just built this stir plate from spare parts. Cost me nothing. On the other hand, I'm an electrical engineer so my home lab bench has a *lot* of spare parts.

The air flow from the fan blades keeps the motor cool. Also adds some mechanical resistance in case the stir bar spins into the weeds.
 
i see everyone mentioned harddrive margnets, cant I just glue a regular magnet on that fan?

You can, but be prepared for it to not be strong enough. The reason many people cannibalize old hard drives for their read/write magnets is because they are super strong neodymium magnets. As an added benefit, if you've got an old hard drive lying around, they're practically free. Alternatively, you can purchase neodymium magnets from a novelty store or online at amazon and other vendors. If you're lucky, you may be able to find some at your local hardware store. Good luck.
 
You can, but be prepared for it to not be strong enough. The reason many people cannibalize old hard drives for their read/write magnets is because they are super strong neodymium magnets. As an added benefit, if you've got an old hard drive lying around, they're practically free. Alternatively, you can purchase neodymium magnets from a novelty store or online at amazon and other vendors. If you're lucky, you may be able to find some at your local hardware store. Good luck.

A+ response. thanks
 
A+ response. thanks

Wait a sec, you're in Chicago. Just head over to American Science & Surplus up on Northwest Highway and Foster. They have hard drive magnets and other much prettier circular neodymium magnets for sale on the cheap. They also have cheapo power supplies, fans and dc motors, project boxes and everything else to build a pretty slick looking, fully-functional stirplate.

Here's a picture of my two stirplates because 1 is never enough. The one on the right is rheostat controlled and housed in an old external cd drive case. It's pretty homespun and I had to build a blanking plate for the front and rear out of cannibalized sheet metal from an old PC case. It needed to be hammered flat and then ground down to size on my bench grinder. The one on the right is PWM controlled and housed in a radio shack project box. At $8 it was probably the most expensive piece of the build.

Edit: Total cost for both was probably no more than about $30 for all the parts I didn't find/cannibalize. PM me if you'd like help from a local homebrewer with lots of electrical experience. I design circuits for a living as an engineer for a CEMS manufacturer.

img_20130502_132600-60682.jpg
 
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