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Diy Computer-fan Stir-plate Build

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sticksy

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quick question from a noob, how important is speed control? cant you just run it flat out?

thinking ill use a hard drive case as it has a power supply already and slide the fan n magnets in.
 

elcarter

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Just upgraded mine with new fan and a CPU controller that's got a digital fan RPM lcd.

I cant go past quarter without the sir bar breaking out of the already maxed out 6 magnet field.

When I was initially testing at half power my un-glued magnets flew off, whizzed past my head and hid behind the brew stand for an hour.

If you double up button magnets glue them to as well :D

A little bit of rpm control is good - in fact i think needed when you have smaller or larger starters to maintain a good whirl pool and keep the magnet in the magnetic field.

More or less liquid has a decent drag effect and having no control would be hit and miss I think.

Oh yeah super fast fan not so great idea,
 

yum beer

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Do you need to have a vortex all the time or just the starter stirring.

I get it going hard for a few minutes then turn it down enough to just keep the wort moving. Then crank it up every so often to bring in some extra oxygen.
Surely yeast are not happy living in a whirlpool.
 

elcarter

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I'm by no means an expert, I think as long as your knocking the Co2 out of solution so you avoid the yeast volcano you should be where you want to be.

If there's any extra benefit / determent from going faster to yeast production / happiness I'm not sure.
 

Edak

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elcarter said:
I'm by no means an expert, I think as long as your knocking the Co2 out of solution so you avoid the yeast volcano you should be where you want to be.

If there's any extra benefit / determent from going faster to yeast production / happiness I'm not sure.
Tell that to 3068! I had mine on a stir plate, about 1.4 L in a 3L flash and it made a huge mess. I hadn't ever seen yeast climb out when being stirred before but hey where there's a will there a way.

I also believe that speed control is a good thing.
 

elcarter

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Cheers for the link Martin, appears going faster makes quite a large difference.

Now I'm wondering how far out my "Brewers Friend" starter calculations are.
 

LiquidGold

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Finally got around to making my own stirplate thanks to this thread so just thought I'd show how it turned out and ask some questions while I'm at it. First off bit of a noob question, when making a starter for the plate do you just boil the stirer bar at the same time as you boil the wort?

lael said:
I used the same dimmer and am also experiencing a whining noise, did using a fan without LEDs fix that issue? The noise stops when it's turned on full with mine but that kinda defeats the purpose of having wired a dimmer :blink:

Pics



 

MartinOC

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Nice one, Centurion!

If you're making your starter wort from DME in the receiving flask, you may as well chuck the stir-bar in at the same time to make sure it's all sanitised.

Don't worry about being able to run the thing at full-tilt. Home-made jobs aren't perfectly aligned & to run it too fast will just throw the bar, defeating the purpose.

As long as you're getting a good circulation & the stir-bar is centred over the magnets, don't worry about speed. Play around with centring the stir-bar in the middle of the flask as it's running, so it's aligned with the magnets (ie. it goes quiet). Job done. It'll work fine.
 

LiquidGold

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Yeah I'd like to run it lower than full but the noise I'm getting is not from the stirbar. It's definately the fan since the first time I noticed it was just after wiring up the fan and checking how the dimmer worked. Right away as soon as I give it enough power to light the LEDs but not enough to spin the fan there is a ringing/whiny noise emitted. This noise continues as I wind up the dimmer and only stops once on full.

Looking forward to culturing some more coopers yeast and seeing the difference the stirplate will have on the end result.

Cheers
 

MartinOC

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I used a fan that came with it's own potentiometer & never had that problem.

'Just thinking outside the square here:

1. Does your plastic container have any holes in it to allow for/reduce air pressure build-up inside it when the fan is running? It could be that the fan isn't able to lift itself off it's bearings unless it's running at full-tilt & that's the noise problem...?

2. Which way does your fan rotate? Is it pushing air up or down?

Edit: Culturing-up Coopers yeast from a bottle? Give it 3 days & you'll see bugger-all. Don't despair. Day-4 it'll take-off like a train. Patience.....
 

LiquidGold

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Fan spins counter-clockwise and is pushing air down but even with the lid off and before the fan was attached to anything it was already making the noise, even before it begins to spin so it makes me think it had to do with the LED or electrical part of the fan somehow. I might try wiring up another computer fan that has no LED to the dimmer and see what happens.
 

LiquidGold

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So I wired up another fan to the same dimmer and when turned slightly on there was the same noise but much much quieter and when the fan began to spin it was basically overidden by the noise of the fan spinning. So although there are no LEDs on this other fan the noise still existed but didn't matter much at all compared to the first fan that was pretty loud. Now considering removing my magnets from first fan to glue onto second fan, which would mean blue LED in the ferm fridge B)
 

spog

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For anyone interested there is a how to build a stirplate in the latest issue of BYO magazine.
It even has pictures .
Cheers....spog..
 

lael

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ok... so a while back I posted that I had ordered those Delta 1212AFC server fans. Tried controlling them with an LED dimmer... annoying whine. Got interested in PWM control, and then... hmm 4 pin fan.. get realy PWM control. I didn't know how, so I found a post where people were talking about doing it on overclockers forum.

Long story short - a friend helped to build an awesome controller board. I got frustrated trying to make it work properly. Gave up for a while, ordered something else which didn't work for the fans. Gave me motivation to get it worked out.

Behold the stir monster!

stirmonster01.jpg

5L being stirred - turns out that straight walled is harder to stir than conical and that glass is easier for the stirbar to stay steady on (no surprise).

stirmonster02.jpg

There was a post that said faster stirring was better... ;)

stirmonster03.jpg

I can't get the large stirbar to go quite fast enough to do this, but with a 1" one the stirbar gets completely enveloped in air. I was scared the stirbar would launch off and break the glass the first few times... but it slows down pretty quickly when it gets launched (the little one can go all the way to 4000rpm... )

So why do you need a big stirplate? - big starter of course! :D

stirmonster04.jpg

stirmonster06.jpg

stirmonster07.jpg

Hard to tell how far the vortex goes down. Not that far. The stirbar is kind of noisy in the bottom of the 20L handypail.

Next step... stir a fermenting beer for the first two days?

edited: clarity
 

MastersBrewery

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lael said:
ok... so a while back I posted that I had ordered those Delta 1212AFC server fans. Tried controlling them with an LED dimmer... annoying whine. Got interested in PWM control, and then... hmm 4 pin fan.. get realy PWM control. I didn't know how, so I found a post where people were talking about doing it on overclockers forum.

Long story short - a friend helped to build an awesome controller board. I got frustrated trying to make it work properly. Gave up for a while, ordered something else which didn't work for the fans. Gave me motivation to get it worked out.

Behold the stir monster!

stirmonster01.jpg

5L being stirred - turns out that straight walled is harder to stir than conical and that glass is easier for the stirbar to stay steady on (no surprise).

stirmonster02.jpg

There was a post that said faster stirring was better... ;)

stirmonster03.jpg

I can't get the large stirbar to go quite fast enough to do this, but with a 1" one the stirbar gets completely enveloped in air. I was scared the stirbar would launch off and break the glass the first few times... but it slows down pretty quickly when it gets launched (the little one can go all the way to 4000rpm... )

So why do you need a big stirplate? - big starter of course! :D

stirmonster04.jpg

stirmonster06.jpg

stirmonster07.jpg

Hard to tell how far the vortex goes down. Not that far. The stirbar is kind of noisy in the bottom of the 20L handypail.

Next step... stir a fermenting beer for the first two days?

edited: clarity
I'm thinkin a new thread is required!!! Awesome stuff. I'm on my brewing shopping spree ATM, and was seriously just about to go hit up the guys at Digital home brew for some kit.
 

Lord Raja Goomba I

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Finally got a whirlpool.

Big two tips I can give.

The bigger Erlenmeyer flasks are more forgiving speed wise. My fan is 1000 rpm and in a tiny flask too powerful.

2Nd bigger one is, test the stir bar sits flat on the magnet. If one side polarises away, then flip the resistant magnet.
 

Lionman

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I have noticed there are some 3d printed DIY PC fan stir plate designs on Thingiverse. I might have to print one out.
 

tdog_505

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so here is my version of a computer fan stir plate. All up with some scrounged components it cost me about $30... could have saved a couple of dollars by excluding the switch, as the voltage controller has an inbuilt switch, but now i get the external light that shows when its running.

View media item 10943View media item 10944
 
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