Diy Computer-fan Stir-plate Build

[vortex]

I've picked up the parts to build a new dual stir plate, two 120mm fans and two fan speed controllers; hopefully one of these will be powerful enough for a 5L lager starter.

Got both of these up and running now, they spin 5L of water OK in an Erlenmeyer, but 5L of wort at a higher density I'm not so sure about yet.


Untitled by auvortex, on Flickr
(Spot the dummies and baby stuff... one of the reasons I brew!)


Untitled by auvortex, on Flickr


Untitled by auvortex, on Flickr


Untitled by auvortex, on Flickr

Rather than looking for smaller round neo magnets like I had in my old stir plate, I picked up 10x rectangular Neo magnets from a retailer on eBay (I can find specific details if anyone likes, cbf logging into eBay right now) for a decent price, was like $25 for 10 or something reasonable like that. A couple of CoolerMaster 120mm LED fans ($25/both), some PC fan speed controllers ($2 each!) and some tupperware containers nicked from the SWMBO's cupboard and they're basically done. I need to pick up some power sockets from Jaycar and i'm ready for a winter of Lagers!

I can't take credit for the tupperware, I saw the idea here somewhere with the specific goal of catching yeast spillage; have had a couple of overflows with my old stirplate, so this will catch it.

These fans, being 'enthusiast' PC fans are not very high RPM (to keep them quiet) so I can run them at 12v flat out and they don't spin too fast, 1200RPM is their max RPM to be exact. I am planning to pick up some faster fans so the stirplates can both spin faster, but honestly these are still pretty good fans to use and they do generate a small vortex.

The rectangular magnets have ment my small and long stirbars all work perfectly unlike on my old stirplate which only used smaller magnets, only my short stirbars would work in these..

 

[iralosavic]

I've got a similar container! Good idea on the rectangular magnets, mate. Haven't tested my 28mm bar out in 5L wort yet either, but it stirs the crap outta a litre.

 

[Wolfy]

Picked up a 5L flask today (at the price from KegKing its hard to go past), it's only blue food-colouring at the moment, but I'm sure that the stir-plate design outlined at the start of the thread will have no problem with 5L of wort/yeast.

What I did find interesting is that in the shop they do not have the fan mounted on anything at all.
The fan sits on the bench, and the flask sits on 4x silicon bung that rest on the bench around the fan - so simple and so easy.

 

[peaky]

Nice one wolfy. How much was the flask? Keen for one of those as I want to ferment double batch lagers.

 

[Dazza88]

I like those rectangular magnets, do they allow you to use a range of stir bar sizes? My spaced out circular ones will only spin the 1 inch stir bar i bought originally.

 

[Wolfy]

Nice one wolfy. How much was the flask? Keen for one of those as I want to ferment double batch lagers.

List price is $39, but I got mine for $35 - either way very cheap for that size.

 

[peaky]

List price is $39, but I got mine for $35 - either way very cheap for that size.

Jeez! That's a bargain, gettin' me one for sure. I thought they'd be double that.

 

[vortex]

I like those rectangular magnets, do they allow you to use a range of stir bar sizes? My spaced out circular ones will only spin the 1 inch stir bar i bought originally.

They sure do. Up to the length of the magnets will work fine, I have 38mm, 42mm and 52mm stir bars, all are fine. The 52mm is about the limit because of the size of the magnets (they're 50mm total, 25mm each); but you could spread them out and make longer stirbars work OK, at the expense of shorter ones if that's what you wanted to do.

My older stirplate with the round magnets works with the 38mm and 42mm, but the 52mm throws straight away.

 

[Dazza88]

Cool. My stir plate will only spin the 1 inch. i scored a bargain of yeast prep stuff including at least 5 stir bars of various sizes, haven't been able to used them due to lack of being assed to build a new fan with magnets set up. Maybe i will get some of those ones rect. ones.

BTW those cheapo LED dimmers suggested in this thread (or the other one?) has latest fine for me for about 9 months, used it for 48+ hours on starters. e.g http://www.ebay.com.au/itm/LED-Light-Dimme...=item27bfe245da

 

[peaky]

Yeah, those rectangle magnets look the business. I may need to upgrade my stir plate once I get a 5L flask. The current version spins up 2L ok but not sure about a starter more than twice that size. I'm limited to a 1 inch stir bar atm.

 

[iralosavic]

Peaky: you may be surprised. Many people report great success with small bars in large volume worts. I'm crossing my fingers with mine. I'll let you know - I already have a 5L flask, just haven't tested the stirrer on it yet.

 

[peaky]

Peaky: you may be surprised. Many people report great success with small bars in large volume worts. I'm crossing my fingers with mine. I'll let you know - I already have a 5L flask, just haven't tested the stirrer on it yet.

Hoping my stir plate will spin 5L, but if it doesn't then I have another brewery project. I don't really need another project right now, it has taken me 5 weeks so far just to fit a sight glass to my HLT! I think I've spent on average about 4 minutes a week working on it....

 

[iralosavic]

Haha totally on the same page, mate. I have so many unfinished projects and it's not from a lack of motivation, I'm simply needed around the clock at either work or home (two high needs babies). I finally managed to calibrate my sight glass a few weeks ago after months of walking past it and daydreaming lol I'm still waiting to find the time to finish my false bottom. Stir plate has been 2 months in the making (mostly waiting for slow shipping).

 

[Wolfman]

I looked at one of those 5L flasks, thought to myself WOW that's freaking HUGE!

 

[iralosavic]

Haha they are bloody ginormous in flesh and blood. I'm always paranoid I'll break it everytime I move it around. So much surface area to accidentally knock against something.

 

[peaky]

I thought the 2L was big when I got it, looking forward to being able to make some big lager starters with a 5L.

 

[Wolfy]

Haha they are bloody ginormous in flesh and blood. I'm always paranoid I'll break it everytime I move it around. So much surface area to accidentally knock against something.

LOL yep. Getting it out, washing it, and setting it up just to take a few photos - after having a few beers - was not a good idea .... so I decided after doing it yesterday.

 

[Wolfman]

I'm spewing I didn't buy one now!

Got home and SWMBO says you should have bought more as they would make a great flower vase!

 

[peaky]

I'm spewing I didn't buy one now!

Got home and SWMBO says you should have bought more as they would make a great flower vase!

Haha! Spares in case you break one...

 

[Wolfy]

KegKing display their 5L flasks with a DIY stir-plate on their counter.
The mounting setup was so simple and easy I asked them to take a couple of photos for me to share here.

As you can see, the fan simply sits on the bench with 4 rubber stoppers for the flask to sit on, it also seems they've used some type of blue-tack or putty to stick the magnets to the fan.
But no matter how simple it is, it works well: