Tight Arse Stir Plate

[supachikn]

Hi fellas.
Here are a couple of pics of my cheapo stirplate. It's in use at the moment so I can't provide detailed shots of the internals.
I took a 25 CD-R spindle and cut the middle pole out of it. I used an 80mm fan from a disused PC, and put a couple of zinc plated dome head 4-5mm thread screws and put them in the mounting holes so I could adjust the distance of the fan from the top of the spindle and also this provides the structural support for the glass flask. I hot glued it into place as the polypropylene spindle doesn't much like superglue, and epoxy was a PITA. I used small 3x5mm neodymium magnets out of those magnetix childrens toys that were taken off the market (the plastic rods would crack and the magnets fell out, no good for kiddies to eat .) Had alot of trouble initially trying to get the stir bar to bind to the magnets on the fan. Using a 12V supply the bar would whip away from the centre of the flask and just sit at the side and wiggle. Using a 5V supply the fan didn't have the balls to make the thing spin at all. Ended up using a small 7.5v switch mode supply that I just turn on and off at the mains. I did glue the magnets pretty far apart (maybe 25-30mm) so I wonder if putting them more centrally might have worked better at 12V. As you can see from the action shots it doesn't quite have the same punch as a lot of other DIY units out there but it keeps the yeast in suspension well enough. I find I have to use another magnet to locate my stir bar in the centre of the flask before placing it on the plate because the magnets don't have the strength to pull it into place, and my flask isn't totally flat on the bottom, it has a central plateau.

 

[Wolfy]

Awesome stuff, planning and visiting ebay now.

It's difficult to search for speed-controlled fans on the net and that model isn't on PC case gear. In the spirit of being a tight arse, i am looking for the cheapest option. Are the LED dimmers easy to connect up to a PC fan? Would i be looking for a specific type of fan if i went the LED dimmer route?

Google search for the model number brings up a few Australian suppliers, but if you can't get them on special using a 2nd-hand computer fan and an LED dimmer might be cheaper/easier.
The dimmer should be very simple to wire up since only has 'in' and 'out' ports which are clearly labeled (according to the Ebay pics I looked at).

They have a little switch that you can flick and it changes the speed.

I find the variable adjustment much easier to get things going well, rather than just a couple of set-speeds.

Here are a couple of pics of my cheapo stirplate. It's in use at the moment so I can't provide detailed shots of the internals.

Nice work, I'm just not sure I'd trust a 2L flask or 5L demijon on one of those CD spindles.
I found that if you put the magnets as far apart as your stir-bar is long it seems to work well.
If they are not glued on too tightly you might like to adjust the magnets and/or how far from the bottom of the flask they are, because they should easily 'grab' the stir-bar when you move the flask over the top of them.

 

[keifer33]

Ah very good point Wolfy. Will have to get onto making one of these soon as I have most of the parts lying around.

 

[Dazza88]

So Wolfy, led dimmers wire up like a switch? Red wire in then out? Looking at the ebay listing l guess that the power supply wire go into v in and then the wires coming out will connect s per your above explanation.

 

[argon]

So Wolfy, led dimmers wire up like a switch? Red wire in then out? Looking at the ebay listing l guess that the power supply wire go into v in and then the wires coming out will connect s per your above explanation.

Dazdog and alternative to a speed controlled fan is to use an adjustable voltage power pack like this one.

They're available at Jaycar reasonably cheap and can be used for all sorts of things.

I use one in my stirplate and just adjust the voltage, which in turn adjusts the speed of the fan. I've also installed a small plug in the jiffy box, which the fan is connected to, so i didn't have to cut the chord. This way i can use the power pack for other stuff.

All you really need is a pc fan, some magnets, a stir bar, an adjustable power pack and something to house it in to have a workable plate.

Unfortunately reading this entire thread gets pretty confusing for a guy like me who doesn't really understand electronics too well. All this talk about capacitors, potentiometers and wotnot... did my head in. But i ended up getting it worked out.



(i tried some speed control as you can see by the little knob... but ended up by passing it)

 

[Dazza88]

Thanks argon,
That might be better as I have old computers with fans.

Hey, you being a brisbanite, was going to ask about water additions for mash. If there was a general suggestion for brissy water? But typing on phone is annoying so ask more detail later.

 

[Wolfy]

So Wolfy, led dimmers wire up like a switch? Red wire in then out? Looking at the ebay listing l guess that the power supply wire go into v in and then the wires coming out will connect s per your above explanation.

The LED dimmers have in/out ports for both the + and - (red and black) wires.
You'd attach the red/black power-adapter wires to the 'input' side, and the red/black wires from the fan to the 'out' side.
That would work for the two main types of LED dimmer on ebay:
http://www.ebay.com.au/itm/LED-Light-Dimme...=item2a1175b21c
http://www.ebay.com.au/itm/Wireless-Remote...=item2a11438358

If you need to buy a power-adapter getting a variable voltage one as argon suggested works fine (but can be more expensive), however they only allow speed control in steps (exactly the same as the 3-speed fans linked by keifer33), not gradual changes from slow to fast, which can be nice.

 

[Dazza88]

Yeah, might go the dimmer route.

Thanks guys.


Anybody buy stirrer bars from o/s (e.g. china) or just go local? Are pivot or egg stirrer bars better?

 

[Wolfy]

Anybody buy stirrer bars from o/s (e.g. china) or just go local? Are pivot or egg stirrer bars better?

I assume that even the 'local' ones are made in China, so if you find a (cheap) O/S supplier let me know, I need a couple more.

But no, pivot bars tend to be very noisy and do not work any 'better' for growing yeast-starters.

 

[Dazza88]

I have checking ebay, pivot type are by far the most common.

I was thinking this one. http://www.ebay.com.au/itm/New-1-5-egg-PTF...3#ht_2341wt_905

says suitable for 500 ml to 1000ml .

This shop appears cheap: http://www.ebay.com.au/itm/VWR-Scientific-...05#ht_500wt_922

But i am not sure what the local prices are.

Noise isn't a huge concern as my brew room is far away from my bedrooms (and is small and reasonably constant temp)

 

[Dazza88]

labdirect dot com dot au seem reasonable?

 

[jonw]

Here's my TASP. Had to buy the magnets (from Jaycar) and the film cannister from Reverse Garbage (so almost free), but otherwise it's completely scrounged. Also bought my stirrer bars from Livingstone - ordered yesterday, arrived today.

Here are the inner workings. I'm using a Zalman "fan mate" fan speed controller (i.e. voltage not PWM) I had around.



and with the lid on..



and in action...



The 20mm stir bar gets a slimline vortex going and is almost silent. The 40mm bar is shown in the pic above, but makes quite a rattle - might have to save that for starters done in the ferment fridge. Looking forward to getting to work on some yeast!

Cheers,

Jon

 

[a1149913]

I've got 1.5L flasks and was wondering what size stir bar would be alright for 800mL starters?

Also do the stir bars have to be magnetic?

 

[Wolfy]

I've got 1.5L flasks and was wondering what size stir bar would be alright for 800mL starters?

Also do the stir bars have to be magnetic?

Yes they need to be magnetic or they will not work.
I find that a size between 20 and 30mm works fine for my DIY-computer-fan-setup.

 

[MaltyHops]

Here is my attempt ... had all the parts from my bit-n-pieces collection
except for the magnets (ebay) and thanks to DrSmurto for the stir bar.



T.

 

[felten]

Finally put mine together tonight for a test run, the magnets took over a month to arrive. >_<

Stirbar, fan controller and magnets sourced from eBay thanks to Wolfy's DIY thread. Here it is at full power 3L flask, 1.5" egg shaped stirbar, and it's ineffably quiet.


The case is an old Tupperware container. Also an 80mm fan and 10 x 10x2mm magnets stuck on, split evenly on both sides. They're spaced the same length apart as the stirbar.

 

[Gar]

Finished my T.A.S.P this morning, It'll get christened this weekend on a strong scotch ale

How long before brew day do you guys make your starters with a stir plate?... 24hrs?

 

[mika]

Sweet looking case ! what's it from ?

After all the talk earlier in the thread about people burning out the pot's and LC's real simple explanation of the speed control circuit, I don't understand why people are still building stirplates with an inherently flawed design ?

 

[Gar]

Sweet looking case ! what's it from ?

It's from a wine tools gift set

After all the talk earlier in the thread about people burning out the pot's and LC's real simple explanation of the speed control circuit, I don't understand why people are still building stirplates with an inherently flawed design ?

Oh ohhh, have I missed something important here?

I'm using a simple circuit with a 1k pot, it's been running all morning on close watch so far

 

[mika]

The pots seem to burn out over time. They'll last for quite a while, but then ultimately die. Hence the circuit LethalCorpse came up with. Pretty simple and cheap, lot of people built it and using it quite happily as far as I'm aware.