Stir Plate build - magnets?

[DaveGillespie]

I'm planning to build a home made stir plate. Does anyone know if these magnets would be suitable?

http://www.ebay.co.uk/itm/Super-Strong- ... 2c76cca538

[Oli1979]

I used similar magnets to these.
Mine are about 9mm x 4mm thick. And they seem to work fine.
How many magnets do you need?
If your just after 2, i'l post you them?

[Oli1979]

This is a post from another thread. Hope it will give you ideas?


So i started to get my shopping list together of various bit i would need. These inclueded power supply 12vdc, 3w potentiometer, on/off switch (optional) and 12vdc fan (like out of a computer). Stir bar (ebay), and 4mm x 10mm dia magnets.
A few bits of solder here and there and i got it working before installing it into a box.
I did try a 5vdc phone charger first, but this was under powered and the fan kept stopping when the stir bar got near it:-

Screwed it all together and got it sat inside the enclosure. when i put the stir bar on, the central fan moved up, and the magnets started to rub, so stripped it all down again! Used bigger spacers this time.
Finally got it all in, see below view:

For an extra finishing touch i found a green power neon which looks cool, and a rubber mat for the glass jar to sit on:-

Then to test, to see if its powerfull enough to stir a litre starter:-

Brill, it works. Its quite difficult to get the stir bar to pick up on the magnets before switching the unit on though!

[Fil]

one tip glue the magnets on a day apart. i did mine on the same day and the slid together in the epoxy due to magnetic attraction duh!!

[Mr. Dripping]

one tip glue the magnets on a day apart. i did mine on the same day and the slid together in the epoxy due to magnetic attraction duh!!

that's the kind of thing I'd do tbh, and one of these is on my to do list so it was good to get the heads up on that.
Nice, tidy job Oli

[Fil]

u can see the tracks in the glue here..


still works tho..



not anywhere near as tidy and polished as Oli spankin job, but all i had to hand was the psu, fan and blutac

[paulg]

fil what is the golden coloured disc on the fan that the magnets are glues to.I have the same fan ,psu anda magnet from a hard drive and plan to build a stir plate sometime soon

[Oli1979]

Well as long as it does the job Fil. It doesn't matter what it looks like.
Can i ask where you got your lovely 2 litre jar from? Its the dogs!

[Fil]

paulg- its a brass washer from the plumbing spares box, originally used for securing a copper hex coil in a copper cylinder, but if your pulling a hdd for the magnets, why not pull a platter out for the same sort of idea, if bigger than the diameter of the fan a 2p coin may raise it high enough, i centred mine bu popping on and slowly spinning with a low voltage nudging it central when needed, it was harder than it sounds, but do-able.

Oli - it came from the copper kettle online brewshop, i dont know it its particularly great vfm but if it should fail its come from a trusted seller its been boiled on the gas hob a few times