OK, here goes, bare with me…
1. Using a hole saw the same size as the fan {not the whole unit, just the fan}
cut a hole in middle of the lid. Old computers have the fan already mounted in
a square plastic surround so you can simply screw the whole shebang under the
lid. I don't think modern computers have this fan setup anymore, it's just the
fan fitted to some crappy junk mounting, always cutting costs I guess so find
the oldest computer you can.
2. Cut that plastic speaker cover off an old radio or something larger than the
hole so you can screw it onto the lid to cover that hole, this is so magnet can
spin the stir bar through all the holes/slots in the plastic. Without that
hole the magnet won't spin the stir bar, lid is too thick. Also make sure you
cut it big enough to sit the brew vessel on. I countersunk the holes in the
plastic and used countersunk screws to keep screw heads flush with the plastic.
Be careful countersinking though as plastic is weak.
3. With the magnet you ripped out of the hard drive, {think there's actually
two magnets in the hard drive} find the sweet spot on the centre of the fan and
fix one magnet to it with double sided tape or glue or whatever. CAUTION: You
will first have to power the fan up with 12v DC to find that sweet spot as the
magnet is moon or crescent shaped. Stick it on with blue tak or something that
you can easily remove so you can fix it properly once sweet spot is found.
Mark the fan when you can power the fan up and it doesn't shake in your hand,
that's the sweet spot for the magnet, now stick the magnet onto the fan hub
properly.
4. Fix the fan {with magnet attached} to the underside of the lid.
5. Screw the speaker cover on the outside of the lid to cover the hole you cut
out.
6. Drill and fit female jack for the power adaptor anywhere you like on the
side of the box somewhere. Of course ensure the jack fits the adaptor first.
7. Drill and fit an on/off switch on the side of the box somewhere {this is
optional}
8. Now simply solder all wiring in circuit from adaptor to switch to fan and
back to adaptor to complete the circuit and you're done.
Stir bars are magnetic. You should be able to purchase stir bars on EBay or
somewhere. A laboratory supplier should have them also.
Hope I haven't left anything out Joe. If I thought I could put photos up I
would, but as I can't edit after posting I daren't do that in case I stuff
something up and can't undo it <g>. I'm a computer numpty.
If I haven't explained adequately just give me a shout, or someone else will
put you right.
N.
Date: Sun, 19 Jan 2014 23:02:25 -0500
From: [email protected]
To: [email protected]
Subject: Re: CS>Where to buy generator(to Neville)
This would be way easy to build if I had an idea of what you are
proposing. Not enough explanation, like where to put the parts. What
is a stir bar? I know it stirs, but how?
A drawing would be very nice!
Joe
On 19/01/2014 5:57 PM, Neville wrote:
A bubbler is not the way I would go either. If you
know someone who is handy with their hands and a soldering iron
you can make your own magnetic stirrer, all you need is….
1. Fan from an old computer
2. Magnet from hard drive of same computer
3. Adaptor converting mains AC power to 12v DC. A variable
converter is ideal and set on lowest setting that keeps stir
bar spinning e.g. 4.5v
4. A jewellery box, they also have a draw for storing stir
bar/s
5. A hole saw the same diameter as the fan to cut hole in
the lid of the jewellery box
6. A square or round piece
of plastic speaker cover cut from an old radio or something
similar for sitting brew vessel on when affixed to the lid
over that hole
7. A stir bar
8. An on/off switch fixed to the box and wired in the circuit
is optional
Wire all the above together and you've got a magnetic stirrer
that works perfectly.
N.
Debbie
