How to build a stir plate for less than ten quid

[strange-steve]

Good guide. I'm definitely considering doing this to increase my yield.

What size of stirrer did you use?

Fwiw I'm actually going to order one of these stir bars to use instead. I found the one I have with the little ridge around the center is quite noisy when going at speed and it is rather irritating. The one I've linked to here apparently solves that problem.

 

[strange-steve]

I've got all the parts except the stirrer now. Hopefully I can get it ready in time to build up some Wyeast American Ale II for my upcoming Black IPA.

Good work, I used mine a couple of weeks ago for the first time for a black IPA. The stir plate worked great, the beer not quite so great :-?

 

[cheapbrew]

The last part arrived in the post this morning so I hope to finally put this together now, I'm gonna use a plastic food tub until I can find a better box.

 

[cheapbrew]

I've wired the power supply to the controller power input and the controller motor output to the fan, but the fan only starts turning when the knob is turned almost full on, and the fan comes on flat out and if I turn the knob back just a fraction it stops, there is not really any control of fan speed?

If I'm really careful with turning the knob I can get it going a bit slower but not much, I managed to get it going slower once and it squeaked like crazy and got slower and slower and eventually stops,

Anyone have any ideas?
Roughly what speed should it spin at?

 

[JapanBrew]

Could it be that some fans are rated for 12v only while other fans fun from 5v to 12?

 

[strange-steve]

I've wired the power supply to the controller power input and the controller motor output to the fan, but the fan only starts turning when the knob is turned almost full on, and the fan comes on flat out and if I turn the knob back just a fraction it stops, there is not really any control of fan speed?

If I'm really careful with turning the knob I can get it going a bit slower but not much, I managed to get it going slower once and it squeaked like crazy and got slower and slower and eventually stops,

Anyone have any ideas?
Roughly what speed should it spin at?

:hmm: Not sure why this is. With mine I have to turn the controller up to about 75% to start the fan but then I can turn it down quite a lot. I can get it spinning as low as 1 or 2 reps per second. Presumably you've checked that nothing is touching the fan or adding friction anywhere? It definitely shouldn't squeak, it should turn very easily.

 

[strange-steve]

Could it be that some fans are rated for 12v only while other fans fun from 5v to 12?

I don't think so because technically a pwm doesn't lower the voltage it just switches it off and on quickly.

 

[cheapbrew]

After trying another power supply and then testing the controller with a bulb, I finally tracked down the problem to the fan, I dug out another fan and it works beautifully now (sp don't buy the fan linked in the parts list) and just as strange said it needs a bit more than halfway to start against the torque of the motor but once its spinning I can slow it right down. Happy days!

The only question now is I can spin it with no visible vortex, or with a vortex going right down to the stir bar as in strange's picture in OP, but I think it needs to be about an inch or so vortex from the top just like in Jamie's photo in post 6 above?

 

[strange-steve]

After trying another power supply and then testing the controller with a bulb, I finally tracked down the problem to the fan, I dug out another fan and it works beautifully now (sp don't buy the fan linked in the parts list) and just as strange said it needs a bit more than halfway to start against the torque of the motor but once its spinning I can slow it right down. Happy days!

The only question now is I can spin it with no visible vortex, or with a vortex going right down to the stir bar as in strange's picture in OP, but I think it needs to be about an inch or so vortex from the top just like in Jamie's photo in post 6 above?

Glad you got it working, it's a shame about the faulty fan. The one in the link is the exact one I got, I suppose for that price the quality isn't gonna be amazing, but it should at least work.

As for the vortex, I believe you are correct, only a small dimple is required. It's main function is to keep the yeast in suspension so a fairly gentle stir is good enough.

 

[chimpo]

:hmm: Not sure why this is. With mine I have to turn the controller up to about 75% to start the fan but then I can turn it down quite a lot.

You need to turn it up to get the starting torque once its spinning it requires very little torque hence u can trim down the pot ( voltage divider)

 

[cheapbrew]

I've been fine tuning it, trying different heights for the fan and different positions for the magnets, got it running really sweet, thanks again for posting the thread Steve :thumb:

 

[JapanBrew]

Yes. Really is a good post. I was about to buy one on eBay for 30 or so, but I have a bunch of fans laying around from old PCs. I'll give this a shot.

 

[cheapbrew]

If you have a hard drive, there are lots of vids on you tube with folks using magnets from hard drives, I didn't have one, so I splashed out a quid on some.

 

[Personal91]

Fwiw I'm actually going to order one of these stir bars to use instead. I found the one I have with the little ridge around the center is quite noisy when going at speed and it is rather irritating. The one I've linked to here apparently solves that problem.

Which size did you go for ?

 

[Personal91]

I've wired the power supply to the controller power input and the controller motor output to the fan, but the fan only starts turning when the knob is turned almost full on, and the fan comes on flat out and if I turn the knob back just a fraction it stops, there is not really any control of fan speed?

If I'm really careful with turning the knob I can get it going a bit slower but not much, I managed to get it going slower once and it squeaked like crazy and got slower and slower and eventually stops,

Anyone have any ideas?
Roughly what speed should it spin at?

Just an idea that should not be attempted by anybody with or without any electrical knowledge as this is potentially dangerous without the correct equipment

Sounds current sensitive - try powering a light bulb that can work with a dimmer with this and see how it goes


Just an idea that should not be attempted by anybody with or without any electrical knowledge as this is potentially dangerous without the correct equipment


Then add the bulb to the circuit as it will act as your load( current)

 

[strange-steve]

Which size did you go for ?

I got the 9x25mm

 

[Personal91]

I got the 9x25mm

thanking you for the heads up

how long did the magnets take to come from china - im not in a rush to build this stir plate but am still intrested

 

[johnnyboy1965]

Maplins sell excellent boxes for about £10.00. V. professional finish

 

[johnnyboy1965]

Maplin Component Box

 

[Bunglebrewsbeer]

Oooohhhhh might try build one myself.


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