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

[JayMac]

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

Thanks, it is a 2" bar in a 2L flask. It's one of the cylindrical bars that have a thin strip in the middle with a slightly larger diameter of the cylinder. If the 1" bar doesn't work I'm going to try the oval bars.

 

[mcbaumannerb]

I've been using a 1" bar (w/o the center ridge) in my 2L flask and it gets a great vortex (I've had a 1.75L starter to date)

 

[emjay]

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!

It's not weird at all. There's too much drag to match the fan speed with the given level of magnetic attraction. There are 3 ways to overcome this:

1)Less drag: Smaller stir bar

2)Increased magnetic attraction: Stronger magnets (hard drive magnets suck IMO, and good rare earth ones only cost a couple bucks) or getting the current magnet(s) closer to the stir bar.

3) Slower fan: More resistance may do the trick, but it may stop starting before it stops throwing the bar. In that case, you need an actual slower fan. Try getting one rated for less than 1000rpm at full voltage.

 

[JayMac]

It's not weird at all. There's too much drag to match the fan speed with the given level of magnetic attraction. There are 3 ways to overcome this:

1)Less drag: Smaller stir bar

2)Increased magnetic attraction: Stronger magnets (hard drive magnets suck IMO, and good rare earth ones only cost a couple bucks) or getting the current magnet(s) closer to the stir bar.

3) Slower fan: More resistance may do the trick, but it may stop starting before it stops throwing the bar. In that case, you need an actual slower fan. Try getting one rated for less than 1000rpm at full voltage.

That makes a lot of sense, thanks for breaking everything down. I'll try the smaller stir bar, adding my second HD magnet, and getting it as close to the top as possible.

 

[JayMac]

Emjay, with the smaller stir bar, it works perfectly!


On the lowest setting, I get a full vortex that periodically smashes into the stir bar and disperses the air throughout. This seems a little aggressive for the lowest setting (the highest setting is madness!). Is there any reason to make an adjustment? Or should I just leave it alone and always leave it on the lowest setting?

Thanks for all the help!
Jay

 

[JuzDuky]

should I just leave it alone and always leave it on the lowest setting?

You'll find that when you are stirring wort and yeast, the mixture is more viscous than plain water so the vortex won't be as aggressive. That's when your higher speeds will come in handy. Best way to find out how it's going to work is to give it a real-world test with a starter.

 

[brewkinger]

Thanks for this.

Just finished up this build.

Went with 8x6x3 box since that was all Radio Shack had.

Ran into only one small issue and I remedied it, but not exactly sure what was "really" causing the problem.

I ended up mounting everything pretty much the reverse as this design, I am using the aluminum as the top of my plate.

I mounted the fan but when I was testing it, for some reason the fan would stop when I put the stir bar on.

The remedy was to mount the fan with a couple of washers and a rubber grommet as spacers, ending up about 3/8" from underside of surface.

The fan ran best when there was that amount of space. Only thing that I can deduce is that the air that the fan was displacing was somehow causing the problem.

WORKS NOW THOUGH!!!

Will get starter on tomorrow and brew on Wednesday!!!

 

[JosR]

I couldn't get mine to work with other wiring diagrams, either, so I tried this one. It burned out my fan. No movement, the LED didn't light up, the fan just smoked and died. I double checked the wiring. It was correct. The power supply was a 12V, 1000mA and the fan was 12v 2.0A.

Aside from buying a new fan, any suggestions?

Thanks

 

[BansheeRider]

I couldn't get mine to work with other wiring diagrams, either, so I tried this one. It burned out my fan. No movement, the LED didn't light up, the fan just smoked and died. I double checked the wiring. It was correct. The power supply was a 12V, 1000mA and the fan was 12v 2.0A.

Aside from buying a new fan, any suggestions?

Thanks

Yeah just buy one from stirstarters.com ($40) and be done with it. Comes with a lifetime warranty too.

 

[DPB]

Planning on building this stirplate and wanted to know what modifications (if any) I should consider so that it would work comfortably with a 5 liter flask. Thanks.

 

[JosR]

"...buy a $40 stir plate and been done with it..."

It's been pretty time-consuming and frustrating for something so simple, so yea, I'm just about ready to buy one instead.

 

[BrewingGunner]

15 min and under $12. Works great with a 2000ml flask.

 

[longcj2]

I am in the process of my stir plate build have everything working but need the project enclosure, I think I might buy new magnets as well but what I have rigged up is made of parts from an old computer and the rheostat is from an old mini fridge do you think that is sufficient enough? What's the advantages of an led on a rocker switch besides knowing its on?

 

[joetothemo]

I'm building this stir plate. I have a 12v fan (black/red wires) and a 12 v DC power adapter (2 black wires).

The DC adapter has 2 black wires. One has tech specs in print. The other has long white rectangles printed on it.

Which goes where?

I'm DIY challenged and appreciate your help.

Joemo

 

[cjhammel]

I'm building this stir plate. I have a 12v fan (black/red wires) and a 12 v DC power adapter (2 black wires).

The DC adapter has 2 black wires. One has tech specs in print. The other has long white rectangles printed on it.

Which goes where?

I'm DIY challenged and appreciate your help.

Joemo

Usually the black wire with white stripe is the positive (red wire on the fan) you can test by holding the red and black/white wire and black wire on fan and the other wire together. If the fan spins it's wired correctly if not switch the wires and try again. Just don't allow the two wires from the wall-wart to touch you can fry the wall-wart.

 

[Grandpasbrewery]

Just finished mine today! Although it wasnt $12-25! Went a little overboard and get the biggest most powerful 120mm computer fan I could find. Coupled with a 12v wall wort and a 50ohm rheostat I hope to do some 3/4L starters for the bigger brews I like. Just waiting on my flasks and stir bars and I'll dial in the magnets.

Quite pleased with how it turned out! I'll post some pics and video once I get everything else!

 

[Hamsterheadsalem]

I found in building mine that a smaller power supply like 6 or 9 volt is plenty. I started with a 12 volt and it was to strong even on the lowest pot setting. It kept throwing my stir bar . The 6 volt I am using now is sufficient. I have made 2 starters with it so far with no problems.

 

[joetothemo]

Usually the black wire with white stripe is the positive (red wire on the fan) you can test by holding the red and black/white wire and black wire on fan and the other wire together. If the fan spins it's wired correctly if not switch the wires and try again. Just don't allow the two wires from the wall-wart to touch you can fry the wall-wart.

Thanks! I eventually figured it out. I am up and running now. Good thing too, because my brother in law has requested a Belgian Triple and it's going to require a gargantuan starter of a strain I don't already own. Looks like this thing is getting a workout in week one.

Cheers!

 

[longcj2]

Alright well i built mine and its not moving enough to displace water so I'm going to make sure there are good connections on the wires and see if that works.

 

[dchd1130]

I'm not getting a variation in speed. I've got it wired the same as this build, I'm using the same pot as this build, and I have a 12v supply. I've also tried running the ground from the fan straight to the supply. Same problem and my LED on the switch doesn't work. Any ideas as to what I'm doing wrong? I think I've tried every possible way of wiring it.

Edit: I checked the output at the pot. On low I've got 10.2v on high I've got 12.1. Is this not enough to notice a change in speed? Do I need a smaller supply?

 

[Mojzis]

I'm not getting a variation in speed. I've got it wired the same as this build, I'm using the same pot as this build, and I have a 12v supply. I've also tried running the ground from the fan straight to the supply. Same problem and my LED on the switch doesn't work. Any ideas as to what I'm doing wrong? I think I've tried every possible way of wiring it.

Edit: I checked the output at the pot. On low I've got 10.2v on high I've got 12.1. Is this not enough to notice a change in speed? Do I need a smaller supply?

I had the same issue with the 12v supply. Go smaller and it will work. I used a larger fan and a smaller supply and it is perfect now.

 

[dchd1130]

I had the same issue with the 12v supply. Go smaller and it will work. I used a larger fan and a smaller supply and it is perfect now.

Ok, I will give that a try.

 

[rideincircles]

Subscribing for my to do list once I find an old computer.

 

[Newsman]

Subscribing for my to do list once I find an old computer.

Heck, just go down to Harbor Freight (if you have one close by or somewhere else if you don't) and pick up a package of "rare earth magnets." They'll work just fine!

 

[dchd1130]

Ok, I will give that a try.

No luck. I tried a 5v supply. Still not a noticeable variation in speed. 5v is a little weak. It had a hard time starting the fan. Is it possibly a problem with my fan?

 

[Mojzis]

No luck. I tried a 5v supply. Still not a noticeable variation in speed. 5v is a little weak. It had a hard time starting the fan. Is it possibly a problem with my fan?

I doubt it. You have the pot wired correctly? 5v probably won't be good enough. I'm using a 9v I believe.

 

[dchd1130]

I doubt it. You have the pot wired correctly? 5v probably won't be good enough. I'm using a 9v I believe.

Yes, supply goes in the center post and out one of the side posts. With the 5v supply I get a range of 4.1 to 5.1v. Thats a 20% change vs the 10.2 to 12.1 is only a 16% change. So Im gonna guess that with a 9v supply Im going to go from 9v to 7.5v. Is there a way to get a wider range? I would think a 30% variance would be a lot better. It just seems like your not going to see much of a change in speed with sub 20% changes. Like I said I cant visually see any change.

 

[LovesIPA]

I used a 6V supply and I can barely turn it on before it throws the bar. 12V is too much IMO.

 

[dchd1130]

Ok, I found an adjustable supply. Its 300ma vs the other was 12v 800ma. I can turn this one all the way up to 12 or back it down to 6. Between that and the pot Ive got plenty of adjustment.

 

[Mojzis]

Ok, I found an adjustable supply. Its 300ma vs the other was 12v 800ma. I can turn this one all the way up to 12 or back it down to 6. Between that and the pot Ive got plenty of adjustment.