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

Slow_Day said:

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.

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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.

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.

Slow_Day said:

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.

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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!

bd2xu said:

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!

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

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?

pannell77 said:

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?

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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.

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.

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

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??

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.

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.

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?

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.

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?

LovesIPA said:

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?

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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.

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

kenais said:

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

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Yep... Me.

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!

JayMac said:

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!

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

mcbaumannerb said:

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

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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.

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)

JayMac said:

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!

Click to expand...

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.

emjay said:

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.

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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.

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

JayMac said:

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

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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.

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!!!

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

JosR said:

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

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

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.

"...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.

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

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?

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

joetothemo said:

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

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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.

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!

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.

cjhammel said:

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.

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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!

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.

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?