'How to' make a "Yorkshire" stir plate

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guyb

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Mine's a "Yorkshire" stir plate, as it's made in Yorkshire by me, and I'm a tight wad :grin: :grin: :grin:

Ok, there are a few websites that give you the basics, and a couple of really good videos:

Here's the basics: http://www.instructables.com/id/Magnetic-Stirrer

And here's a two part video:
Part 1: http://www.youtube.com/watch?v=WnBr3ZOHOSg
Part 2: http://www.youtube.com/watch?v=0UfzE--pc5A

<edit> I also forgot to mention in my original post that there is also an excellent 'How to' already on the forum, I meant to post the link but forgot: viewtopic.php?f=30&t=11441 <edit> :thumb:

So you will basically need:

A 12v PC case fan - you can pick these up from ebay for about £2 free delivery, or you could scrounge one from someone throwing a PC away, or you could "borrow" one from the tip / dump next time you go :grin: , as there are always loads of PCs in the scrap metal recycling. Mine came from a Dell PC which had an airchute (a bit like a funnel) directing the air from the fan to the CPU - as you can see in my pictures, the fan casing came in very useful.

12v power supply – I had a spare external DVD RW power supply, but I've also got another from a now dead and defunct Black & Decker drill (more on that later.

Magnets – I extracted two from a dead Hard Disk Drive, but I found these weren't quite strong enough, as they were smaller than I expected. So I got a couple of N40 Neodymium magnets from ebay (N52 are stronger still) for £3.49 (item 150665963882) delivered from Spider_Magnets (arrived next day).

A DVD case, mine happened to be a clear one, but it doesn't have to be, I did find however that the original CD jewel case front I had was too brittle when trying to cut it down, whereas a DVD case can be cut with a Stanley knife.

Optional extras:

12v socket – you can cut the wires off the 12v power supply, but I had an idea that I could salvage the 12v socket from the Black & Decker and make a better looking finished article – so I took the drill apart and took it out – or you can but one from Maplin's if you want to: http://www.maplin.co.uk/components/conn ... connectors

Switch – I put a simple on / off rocker switch that you can get from a car spares shop or maplins / similar. I picked mine up from a new shop called “The Range”.

Some tools you will need are:

Blue Tack
Soldering Iron (if you want to solder the wires, you can use spade connectors or even a terminal block if you want)
Glue Gun
Drill
Stanley knife

Here's some pics to show the assembly

The extracted fan, and various bits and pieces:
6e50e4b7.jpg


A close up of the fan housing – note the rubber “bushes” on the four corners of the fan housing:
af3b7670.jpg


The fan (note I got the hoover on it, as it was full of dust and crud from the years in the PC) – you can see that I have mounted the rocker Switch on the case fan housing:
db0b7a22.jpg


A close up of the DC socket taken out of the Black & Decker drill:
b6eb4b1e.jpg


Here's a hole I drilled into the fan housing, I am going to mount the 12v DC socket in the recess:
10756e4d.jpg


And here's the DC plug in the socket – it will be secured by glue from the glue gun, you can see it whizzing away:
fc8492b8.jpg



Here's the glue going on, note I put the magnets on the fan first with Blue Tack to check the concentricity of the spin of the fan, and then marked them with a pencil.
I then marked the upward face of the magnet with a T for Top!, and added a good dollop of hot glue:
db275f14.jpg


Here's the clear DVD case prior to it being chopped up:
ea89387e.jpg


And here's the finished article doing it's job - the stir bar is one of the stainless steel pins I extracted from the CD drive in my other post on Stir Bars in unlikely places.
367bf1af.jpg


You can see that the fan casing has what I'd call rubber standoffs which hold the fan tight in the case without causing any noise from vibration. I used these to hold the cut down to size DVD case in place just push the cover on, and tug the rubber upward.

Total cost (I had most of the parts already, plus a glue gun and soldering iron):

£3.49 for the magnets
£1.25 for the rocker switch

Less that a fiver!

I've got a proper 1000ml borosilicate flask in the post from ebay for £3.95 (item 150628256772) – although it works perfectly well with a milk bottle and an ordinary bung / airlock from a 25L fermenter.


Hope it was of some use
 
hairybiker said:
Just remind me, what are these used for? (apart from stirring tea, for which. as a tight Scotsman, I use a teaspoon)


According to Aleman: "They do not aerate the starter as such, but help CO2 to evolve from the solution, and keep all the yeast in suspension and in contact with the growing medium . . . It can't be easy for the yeast trying to grow with several million of your compatriots sitting on your head."

From: viewtopic.php?f=30&t=11441
 
Thanks guyb, not ever needed one before, and don't think I will bother now. I only brew 5/10Gal batches and either just rehydrate the yeast or just pitch it and cant say I have ever had any problems in the past 20 years doing this :cheers:

Probably useful if you do large brews or create starters from slants etc.
 
hairybiker said:
Thanks guyb, not ever needed one before, and don't think I will bother now. I only brew 5/10Gal batches and either just rehydrate the yeast or just pitch it and cant say I have ever had any problems in the past 20 years doing this :cheers:

Probably useful if you do large brews or create starters from slants etc.


Absolutely agree, I just felt the need to make one to satisfy my obsession :grin:

I have started using the yeast slants / slopes from Brewlabs which er kind of justifies it in my own mind :grin: :grin:

...and my kids (10 and 12yrs) found it interesting which is always a bonus when justifying these things to 'er indoors (in the name education dear! :rofl: )
 
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