Ok I needed to do 2 brews at the same time a couple of weeks back and wanted a stronger stir plate for my bigger 3l starters
Take a standard computer fan from eBay or an old computer
(http://img.tapatalk.com/d/13/12/17/jede9yda.jpg)
Screw in 4 woodscrews which are marginally thicker than the locating pins
(http://img.tapatalk.com/d/13/12/17/7eny4u8u.jpg)
Get yourself some magnetic adhesive metal strip cut to length and attach to rear of fan
(http://img.tapatalk.com/d/13/12/17/yhuqujy7.jpg)
Buy some small extra strong magnets from eBay and place at either end of your strip, try and ensure they are equidistant from the centre, I have stacked 2 to improve magnetism because of the monster stir bar but I tried a pair on their own with a smaller bar and they were fine.
(http://img.tapatalk.com/d/13/12/17/renugysa.jpg)
Get yourself a variable transformer and connect it to wires of your fan
(http://img.tapatalk.com/d/13/12/17/u6etu9e8.jpg)
Now the tricky bit, it my case I used a piece of Perspex but thin timber or any thin sheet of plastic would do and rest on top ensuring you have a uniform gap
(http://img.tapatalk.com/d/13/12/17/ynevu6ur.jpg)
(http://img.tapatalk.com/d/13/12/17/uzy8evep.jpg)
(http://img.tapatalk.com/d/13/12/17/evumupar.jpg)
Some Ribena in to illustrate vortex, remembering that the trick is not to beat the crap out of it just to keep your liquid yeast in suspension.
9v setting for smaller starters 12v for larger ones
Bigger distance you have between your magnets and stir bar will lead to stir bar flying off, use the screws to get to the correct height.
(http://img.tapatalk.com/d/13/12/17/je4a7e2y.jpg)
How do you get stuff shipped on eBay in 5 minutes? >:D
I have a few banana shaped magnets from trashed Hard drives.
Super strong, I have still to complete my build though :-[
nice, was thinking about doing a similar post. only got as far as afixing the magnets so far. a bit longer then 5 mins :P
Any links for that transformer ? Where did you get the perspex? Cheers for this, so simple when you see it done like this.
Maplin (a bit pricey) do that sort of stuff.
You should be able to get them on eBay.
Quote from: Greg2013 on December 16, 2013, 08:24:32 PM
Any links for that transformer ? Where did you get the perspex? Cheers for this, so simple when you see it done like this.
Perspex is a trade friend but woodies sell it, timber panel is just as good
Magnets
http://www.ebay.co.uk/itm/10-Very-Strong-Neodymium-Disc-Magnets-10x2-mm-N52-Grade-craft-reborn-10mm-x-2mm-/151174834780?ssPageName=ADME:L:OU:IE:3160
Adhesive strips
http://www.ebay.co.uk/itm/6-SELF-ADHESIVE-METAL-STRIPS-STICKY-STRIPS-MAGNATIC-STRIPS-WITH-6-STRONG-MAGNETS-/150754849930?ssPageName=ADME:L:OC:IE:3160
Fan
http://www.ebay.co.uk/itm/120mm-4-Pin-Computer-PC-Case-Cooling-Cooler-Fan-/260922590667?ssPageName=ADME:L:OU:IE:3160
On the transformer I think it was this one, its one I had kicking around for ages
http://www.ebay.co.uk/itm/Universal-mains-power-adaptor-AC-DC-3v-12v-/360382597986?pt=UK_ConsumerElectronics_PowerAdaptors_SM&hash=item53e87a0b62
Cheers CH i had everything except the transformer. ;D
Actually Greg it might have been this one
http://www.amazon.co.uk/Universal-MAINS-POWER-ADAPTOR-300MA/dp/B003BEZ7HI/ref=sr_1_1?ie=UTF8&qid=1387229739&sr=8-1&keywords=universal+transformer
They are both the same and equally as good, I might give the demijohn a go later, you just need movement not
http://www.youtube.com/watch?v=WhQySxqSANU
Ditto on hard disk magnets. I use an old 9v power supply. Also, any old CD works great in place of perspex. They're my tips if you want to keep it real cheap and upcycle.
Old cd is clever and would work, not sure it would be big enough for 3l flask tho?
Dunno. 2L is my largest.
Use an old Laserdisc :P
Laserdisc! Posh! ;)