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

[bd2xu]

I got it all glued down and set up. I got the 5.6v charger to work but it doesn't want to spin the bar. The washer is pretty thick and the magnet is 50 x 10 x 5mm. Maybe its too much weight? Would a higher voltage power source give it extra power to get the 2" bar moving or do I just have too large of a stir bar?

Also my fan is a cheap 2$ fan off ebay, maybe its too sh***y?

Sorry for the continuing questions, but this thing is frustrating.

I can't get my 2 inch bar to spin right with even a 12 volt but my 1 inch one spins perfect with the 12v. Best design is prob a 12v with a potentiometer to slow it down if needed. My design is a cigar box, I think the amt and type of material between the magnet and glass determines a lot. Bottom line every DIY version of a stir plate acts diff and you have to tweak and test

 

[fizgig]

I might turn my 1st gen mac mini into a stir plate.

 

[mojo2008]

I got it all glued down and set up. I got the 5.6v charger to work but it doesn't want to spin the bar. The washer is pretty thick and the magnet is 50 x 10 x 5mm. Maybe its too much weight? Would a higher voltage power source give it extra power to get the 2" bar moving or do I just have too large of a stir bar?

Also my fan is a cheap 2$ fan off ebay, maybe its too sh***y?

Sorry for the continuing questions, but this thing is frustrating.

I found that most cell phone chargers have a much lower current rating that the fans we are trying to power. I started off with a 5V 200mA charger and it spun my fan, but not very fast and definitely not reliable with a starter. My current setup uses a 5V 1000 mA charger and it spins the fan fast enough that it is functional, but it still spins nowhere near as fast (even without the magnet) as it did when it was in a computer. I don't remember the current rating of the fan offhand, but between the voltage and current the charger is well below the fan's values. Ideally, if the charger's output specifications match the fan's input specifications you will get the best performance. In this case though I don't recommend running it without a pot for speed control.

 

[Mojzis]

A friend gave me a 120 mm 12v fan and a 12v power supply they had laying around. Re-did the whole thing and the fan if ridiculously fast now, so that's good. However I haven't got the damn bar to move. I ordered some more magnets online to see if my magnet I have isn't the right shape. I'd hate to spend the 6$ for a one inch bar instead of my 2".

 

[mojo2008]

A friend gave me a 120 mm 12v fan and a 12v power supply they had laying around. Re-did the whole thing and the fan if ridiculously fast now, so that's good. However I haven't got the damn bar to move. I ordered some more magnets online to see if my magnet I have isn't the right shape. I'd hate to spend the 6$ for a one inch bar instead of my 2".

Do you have a potentiometer installed? It sounds like the fan moves too fast for the magnetic fields between the magnet and the stir bar to remain coupled. I find it best to turn it on with the potentiometer set to min speed and then slowly speed it up. Eventually you will find a speed that will throw the bar.

 

[Mojzis]

Yeah the pot's installed, but it still goes pretty fast. However it wont throw the magnet even turned all the way up. I hope its not too fast now....

Edit: just switched the supply back to 5.6v and the bar moves a little more. Maybe the pot doesn't slow the 12v down enough? Maybe I need a bigger pot to use the bigger supply...

 

[bd2xu]

I found success in computer fan, washer, hard drive magnets, cigar box and 12v adapter with 1" bar. It spins perfect with a 2L flask and after centering the washer and magnets its almost silent. Perfect vortex, and I didn't have to buy one thing. I tried 6, 9, and 12 volt adapters and the 9 spun it but the 12 is better. Point is you can do this without buying a pot and doing that wiring if you have a variety of adapters laying around, just have to find the right combo.

I'm using 4 hard drive magnets from 2 old hard drives and man are they strong.

 

[Mojzis]

I thought I had an old hard drive to harvest from but I lost it somewhere.

I got the bar to spin with the 6v, pretty good vortex. I don't have the flask so my growler will work for now. I just cant turn it all the way up because it will slide off the curved bottom. Oh well, it works. Maybe when I get a flat bottomed flash i'll hook the 12v up again.

Thanks guys for your help/advice.

 

[Slow_Day]

Here is mine.
I bought the Radio Shack rheostat and knob and tested it by squeezing my 3" square fan into a round cheese container. Perfect fit! Who needs an $8.00 project box and machine screws?

OK. Its a POS. But it works great! Can't wait to make my first starter.

 

[GrogNerd]

replaced the electronics in my guitar, wondering if a 250kΩ potentiometer will work instead of the 25Ω listed in the OP?

 

[bd2xu]

Here is mine.
I bought the Radio Shack rheostat and knob and tested it by squeezing my 3" square fan into a round cheese container. Perfect fit! Who needs an $8.00 project box and machine screws?

OK. Its a POS. But it works great! Can't wait to make my first starter.

Looks awesome! I'd be careful though looks like it could slide off. And I bet soon you will want a bigger one for a 2L flask. In the meantime may want to put something sticky on the surface to hold the flask in place.

Next time you drive by a cigar store stop in and ask for a box. Many will give away the cardboard ones for free or they might just charge you a couple bucks.

 

[Slow_Day]

Thanks BD. I already plan to use a larger vessel. Didn't figure that out until after I bought the one litre. I think this little guy will push it for now. I let it run for about 24 hours with no issues.

The plastic cheese tub was supposed to be for a quick test of my system, but since it worked so well in testing, and I didn't have a better container on hand, I decided to go with this until I have a need to change, but I don't think i've seen an uglier one.

 

[bd2xu]

Thanks BD. I already plan to use a larger vessel. Didn't figure that out until after I bought the one litre. I think this little guy will push it for now. I let it run for about 24 hours with no issues.

The plastic cheese tub was supposed to be for a quick test of my system, but since it worked so well in testing, and I didn't have a better container on hand, I decided to go with this until I have a need to change, but I don't think i've seen an uglier one.

Redneck engineering projects are what it's all about. There's satisfaction in not having to buy anything for a DIY. Most projects involve multiple trips to the Home Depot... In the same day!

 

[tg123]

Redneck engineering projects are what it's all about. There's satisfaction in not having to buy anything for a DIY. Most projects involve multiple trips to the Home Depot... In the same day!

Lol. I've been there many times. Save money on the project but money is spent on gas instead. Still satisfying though.

 

[pannell77]

so my stirplate works great......for about 10-15 mins then it throws the bar. I have it spinning on the slowest speed, which is the only way I could get it to stay spinning to begin with. Using a 2L flask and 1" stir bar, have a 2" bar on the way and hoping that fixes things. Any thoughts on this?

 

[Roadliner]

so my stirplate works great......for about 10-15 mins then it throws the bar. I have it spinning on the slowest speed, which is the only way I could get it to stay spinning to begin with. Using a 2L flask and 1" stir bar, have a 2" bar on the way and hoping that fixes things. Any thoughts on this?

You can look for a power cord that puts in less power so it will spin slower at the lowest setting I think. And I actually found that my plate will throw a SMALLER bar less often.. I use a 1/2in bar most of the time in my 1l starters.. works perfectly and rarely throws, but every time I put in a bigger one it ends up throwing in a few minutes.

 

[Slow_Day]

Brewgeeks had a great tip to place a small (dip tube) o-ring on each end of the stir bar if you don't have a flat bottomed vessel to stabilize and reduce the chances of throwing the bar.

I haven't tried this, but I it sounds like it would help with domed bottom vessels.

 

[MedicMang]

building mine tonight. Super pumped. Thanks for the info.

 

[Roadliner]

Here's a question that my previous advise a few posts up made me wonder.. I have trouble throwing a larger bar.. and when I get over like 800ml.. I have trouble even holding onto my 1/2in bar with the magnets from the OP. So I'm thinking of getting stringer magnets...

Can I put TOO strong of magnets on it? or will it make no difference as long as it/they are centered??

 

[evolcoms]

I posted a picture of mine and I used 2 magnets that OP suggested. I am using a 1" stir bar. Maybe get a larger washer to adhere the magnets to.


Edited: My bad man I just noticed it doesn't show the magnets on there. I set them on each end of the washer just as wide as the stir bar.

 

[ACC84]

Built this Saturday. Only change I may do would be to use a 6V wall wort instead of the 9V one I am using currently. I had some issues with it throwing the bar until I started messing around with the height of the fan. I like the machine screws because you can adjust the fan housing and make sure it doesn't get too hot in the enclosure.

Thanks to the OP.

 

[msujack]

 

[sethlovex]

How do make the wire connections to the pot? What kind of scrap wire do you use? I have some 14 Romex lying around is this too big?

 

[millsware]

Thanks a lot for the tutorial. I made this a few weeks ago. Did 1 qt. starters this week of WLP 500 and 565. Brewed today and both batches (5 gal each) were going in <4 hours.

 

[LovesIPA]

I don't seem to be having as much luck as others. I built mine but I have a few problems/concerns.

First, computer fans are balanced. If you stick a large magnet on top of the fan, what does that do to its life span? Am I going to have to replace the fan every few weeks/months?

Second, I have been playing around with different magnets, different spacing between the fan and the lid on the box, and I have problems throwing the stir bar, even on very low speed. How much of a "cone" do I need in the wort? Or is a gentle stir enough?

 

[Olive Drab]

I don't seem to be having as much luck as others. I built mine but I have a few problems/concerns.

First, computer fans are balanced. If you stick a large magnet on top of the fan, what does that do to its life span? Am I going to have to replace the fan every few weeks/months?

Second, I have been playing around with different magnets, different spacing between the fan and the lid on the box, and I have problems throwing the stir bar, even on very low speed. How much of a "cone" do I need in the wort? Or is a gentle stir enough?

A cone is cool looking but not really necessary. the wart just needs to be stirred so some oxygen mixes and most importantly the yeast is always on the move.
to make sure I dont throw the stir bar, I move the flask around until the magnet catches the stir bar and then center the flask. I always start super slow and if need be increase the speed. It took a few minutes for me to find a sweet spot as far as how many magnets and their position so keep messing around until you find one that has enough grab for you. The magnets I bought on the cheap at a junk store didnt want to play nice and kept shifting which drove me nuts. experiment and you will succeed!
Ive been using this since last summer and no issues. I would think it is pretty hard to burn out the fan and if it does, so what? its not that hard or expensive to replace.

 

[kenais]

Has anyone been able to stir a 5L flask with this? Maybe the 8x6 enclosure will work better.

 

[Huaco]

Has anyone been able to stir a 5L flask with this? Maybe the 8x6 enclosure will work better.

Yep... Me.

 

[JayMac]

I just wired everything up. I'm using a 12V supply with my 12V fan. Even at the highest resistance from the potentiometer, my bar still gets thrown.

What's weird is that when there's nothing in the flask, it spins fine. When water is in, it throws?

I lowered the fan as far as I can, but it's still throwing. Should I just throw in a resistor? If so, where is the best place to put it, and what should it be rated for?

Thanks! Can't wait to get this thing tuned!

 

[mcbaumannerb]

I just wired everything up. I'm using a 12V supply with my 12V fan. Even at the highest resistance from the potentiometer, my bar still gets thrown.

What's weird is that when there's nothing in the flask, it spins fine. When water is in, it throws?

I lowered the fan as far as I can, but it's still throwing. Should I just throw in a resistor? If so, where is the best place to put it, and what should it be rated for?

Thanks! Can't wait to get this thing tuned!

You bar might be too big. Try a smaller one if you can get it.