Tight Arse Stir Plate

[lickapop]

No worries.
I didn't think about it until now but the same controllers are in my house. When I get the chance I will pop them off the wall and see how the are wired up

Or I will just stare at it long enough that it will come to me. I bet it is real simple lol

 

[Steve@PMF82]

No worries.
I didn't think about it until now but the same controllers are in my house. When I get the chance I will pop them off the wall and see how the are wired up

Or I will just stare at it long enough that it will come to me. I bet it is real simple lol

I have the same kind of fan. I was thinking of buying one of these http://www.ebay.com.au/itm/Fan-Speed-Contr...9#ht_500wt_1202

only $35 - although some of the comments say it looks homemade, they would have to be a sparky to sell such a thing you would think?
Would be good to know how to wire one up with a diagram like stc 1000, but all in all it would prob be safer to get a local sparky to wire one
up for me, whether or not that would work out cheaper than ebay option?

 

[lickapop]

Yeah some of those stc1000 diagrams are awesome. I built a couple of them.
Thanks I saw one of those controllers on eBay. I have a professional manufactured one at home already but you know how it is... It's just another box hanging off your stir plate that gets in the way of your beer mug
I want mine to look sexy.

 

[lickapop]

Either you are confident or you need help ... not both.
Its 240V, it can kill you or someone else, if you're asking for help - stick with the 12V computer fan not a 240V one.

I am confident that I can copy someone who knows their stuff. not a problemI don't want to die. I can strip a wire while it is not plugged in

 

[lickapop]

yet another stir plate.
240V this one. It whirlpools 4-5L right to the bottom

Thanks all... Im stoked.

 

[Truman42]

Just built myself a stir plate but not sure what size stir bar to use. Ive used a hard drive magnet which is 35mm long. So not sure if I should buy a 30mm stir bar or a 40mm one.

Those of you that have used hard drive magents, what size stir bar did you find worked best?

Thanks.

 

[sp0rk]

So after reading the whole thread I've decided I'd like to make a stir plate
while cleaning out a wardrobe today i pulled out an old pc to put out for the council clean up
but first I stripped it of all fans, useful wires, power supply and the old 40gb HDD that was in it
I've gutted the HDD to remove the magnets and also pulled out the drive motor
after about an hour of googling and watching youtube videos, I've figured out I can use the drive motor to power my stir plate
an R/C servo tester for rpm control and a brushless speed controller to convert from DC power to the 3 pole motor
the servo tester was $2.70 and the speed controller was $7.20, both on ebay
the speed controller is rated 20A 6-12v so I can either use a 6v torch battery, phone charger or the computer power supply (which i'm planning on customising into a 12v power supply for other projects)

I'll post more on the progress of this once the servo tester and speed controller get here

 

[ledgenko]

For an active "starter" just run the stir plate until you see some signs of fermentation... ie bubbles running up the side of the flask, start of a krausen etc. Then turn it off. You don't want to be adding oxygen to the wort once fermentation is underway. This will oxide the wort giving off flavours when you add the entire contents of the active "starter" to the waiting wort. You want to pitch active "starters" to the wort at the peak of fermentation, this gives the yeast a running start at the main wort.

For yeast culturing/stepping up, keep the stir plate going the whole time until fermentation is complete. Then crash chill the wort to settle the yeast. Decant the oxidised beer from the yeast cake and either pitch just the slurry to the wort or add more wort to the flask for a step up, in order to produce more yeast.

Totally OT ... Cheers Argon.. My 5 brews I have done each at 50lt which have had a yeasty / off taste ... Maybe explained by your sims explaination...
Cheers

 

[sp0rk]

Well, my hard drive motor stir plate experiment is over quicker than i thought
because of the shaft in the centre of the motor, i can't mount the hdd magnet over the middle
so i ended up just grabbing a project box and switch from jaycar
and using a variable voltage power pack from bunnings
8cm fan and a hdd magnet sourced from old pc
i've got some rare earth magnets coming in the mail, as the hdd magnet seems a little too strong

 

[peterl1981]

hey lads,



I have just made a stir plate, but the pot dose not work properly, it only goes flat out or off, so it only uses one end of pot...



what would be the problem??

 

[christmas]

I pimped mine out with a glowing blue fan and a six buck ebay temperature display

 

[OneEye]

I'm throwing together the bits and bobs to get a build for myself going. I've done a few simple circuits before but just have one question for those out there who have a bit more of a grasp on this than me.

Following along with LC's circuit, it calls for a 680Ohm Resistor. From what I already have laying around, I have 6 100 Ohm and 1 80 Ohm resistors. If I place them together in series will that give me the same result?

 

[leiothrix]

Yes it will, resisters values are additive when placed in series.

 

[OneEye]

I thought so but wasn't 100%. I've knocked it all together and she's working a beauty!

 

[christmas]

When I turn the speed down to a reasonable level, mine emits a horrible high pitched noise. Pretty much anything under full speed will get it.

Anyone know why this could be?

I think it's because I tried to make mine all flash and used a fan with LEDs in it, and they don't take kindly to being dimmed.

I might try stuffing the box full of foam to try and limit it a bit. Failing that, starters are gonna have to be made in closed room somewhere. I really don't feel like replacing the fan, this thing has already been a whole load of dicking about.

 

[blotto]

I think it's because I tried to make mine all flash and used a fan with LEDs in it, and they don't take kindly to being dimmed.

I'm not sure why it would be making noise but I cut the cables to the LEDs on my fan in my brew fridge because light is bad for the yeast, you could give that a go?

 

[NewtownClown]

I'm not sure why it would be making noise but I cut the cables to the LEDs on my fan in my brew fridge because light is bad for the yeast, you could give that a go?

As far as my limited research has revealed, visible light only has an effect on brewers yeast when grown at/below 12C.
Ultraviolet light actually increases the growth rate of yeast and studies proved that beer ferments quicker under UV, however there is a fine line between intensity and exposure time, the UV will eventually kill the yeast.

From that, I'd argue your little LEDs wont cause harm.

 

[blotto]

As far as my limited research has revealed, visible light only has an effect on brewers yeast when grown at/below 12C.
Ultraviolet light actually increases the growth rate of yeast and studies proved that beer ferments quicker under UV, however there is a fine line between intensity and exposure time, the UV will eventually kill the yeast.

From that, I'd argue your little LEDs wont cause harm.

Fair enough please disregard my uneducated comment. I think I'll still ferment in the dark, in more ways than one it would seem

Christmas you could still try disconnecting the LEDs if you think that might be the problem.

 

[bond]

Just fired mine up, my 5L demijohn has quite a concave bottom, it threw the stir bar until I double stacked extra magnets.

It's quiet enough when the whirlpool is only an inch deep, but quite loud when on full tilt - do flat bottom flasks help with this?



I think I'll remove the potentiometer from the PWM board, and mount it and a DC socket into another piece of perspex - more tweaking first though

The pwm controller I used : DC 5V-40V 3A PWM Controller (ebay)

 

[felten]

Are you using a stirbar with the pivot ring? Apparently they can be quite noisy.

Oh I can see it in the pic, you might want to look at an egg shaped bar.

 

[Wolfy]

Stir bars with a pivot ring tend to be more noisy, however they are probably better on the curved base of the demi john.

 

[yum beer]

View attachment 57477

Just fired mine up, my 5L demijohn has quite a concave bottom, it threw the stir bar until I double stacked extra magnets.

It's quiet enough when the whirlpool is only an inch deep, but quite loud when on full tilt - do flat bottom flasks help with this?



I think I'll remove the potentiometer from the PWM board, and mount it and a DC socket into another piece of perspex - more tweaking first though

The pwm controller I used : DC 5V-40V 3A PWM Controller (ebay)

Hey bond,

how do you have the fan attached to the perspex....

 

[bond]

how do you have the fan attached to the perspex....

http://www.pencomsf.com/mechanical/fan_screws.aspx - Had these which came with fan's I've bought in the past

 

[Aydos]

Wow i just finished reading all of this thread, there is some really good info in here.

Need to stop being so lazy and get mine built!

 

[mkstalen]

I bought the parts to do this build a little while ago, and finally got some time yesterday arvo to put it together (little bloke was sleeping, wife was quilting).

Here's the breakdown:
1 x 120mm PC fan (12v, 0.3A) $2.99
1 x LED dimmer (12-24V, 8A) $3.21
1 x Old power supply (12v, 450mA) Free
10 x 8mm x 1mm neodymium magnets. $1.42
1.2L square plastic container pinched from cupboard. Free (I think they're about $5.)
Screws, wingnuts, and rubber feet things $6 maybe.
Total = $20 tops


Pics in the following galley.
http://aussiehomebrewer.com/gallery/album/1010-stir-plate-build/

(Can't figure out how to easily insert them into this post)

My only question is when I have the dimmer turned down all the way the fan is still running, anyone got any ideas why this might be? I thought it'd be off when turned right down...

 

[Amber Fluid]

It is possible the "knob" to control your fan is not set correctly....
Pull the knob off (pardon the pun) then turn the fan down as far as it will go with your fingers. Replace knob and it should be fine.

 

[LethalCorpse]

Most switchmode drivers have a minimum on time for stable regulation. If it's a cheap controller, this can be quite a high duty cycle. The designers of your LED controller may have added a series resistance with your control pot to allow for this, and erred on the side of caution. Either way it's likely to be inherent to your controller and not easy to remove

 

[KingKong]

Quick question my power 12v power supply adaptor. How do i easily know which is positive and which is negative when both are black ? One cord has white dash's on it?

Further im running to a dimmer that says .8 amps my power supply is throwing out 1 amp. Ok or not?

 

[treefiddy]

I think the white stripe is usually positive.

Might be that the dimmer is rated at a maximum of 0.8 amps, but if you're using something that uses less that 0.8 amps (such as a PC fan) then the rating of the dimmer will not be exceeded.

 

[MCHammo]

Just came across this thread, and thought I'd put up my design. Rigged up an old 555 timer I had lying around with a pot, a diode, and a few resistors + caps. I see there is a different 555 design floating around here somewhere. I might as well add mine to the mix.


Schematic for the PWM driver. I used a 100k pot and... can't remember the two resistors. 1k maybe? I'll need to dig out my stir plate later on to check. I've opted for a mosfet to drive the fan rather than a plain transistor. Personal preference - a few less components required, and more efficient.


Circuit board I etched for this purpose. About 25x30mm in size.


Assembled plate (with a few extra switches, plugs, etc.) You can see the PCB between the pot and the fan. Powered by an old PC power supply that I turned into a bench-top power supply... At least until I can be arsed looking for a suitable plugpack. I'm sure I've got one somewhere.