Stir Plate

[LiamTutty]

Cheeky I know, but would anyone have a loan of a stir plate for a few days by any chance? Willing to pay a rental fee for it, no problem.

Thanks,
Liam.

[RichC]

What part of the country are you in?

[LiamTutty]

In Athlone, but will be traveling home to Naas/Blessington area for Christmas.

[johnrm]

Make one.
There are lots of make and dos.
The trick that I have found is to use a spacer between the fan and magnet.

Don't bother with the speed regulator from Maplin, waste of money.

[LiamTutty]

Seen lots of tutorials alright...just haven't had the time to get around to it. I bough the magnets, but that's about it.

[Endatheworld]

Make one.
There are lots of make and dos.
The trick that I have found is to use a spacer between the fan and magnet.

Don't bother with the speed regulator from Maplin, waste of money.

Sorry for Hijacking this thread! 

johnrm - I am putting one of these together at the minute and have all the bits apart from the potentiometer. I assume you have made one without it then? No problems with speed at full throttle?

[mr hoppy]

The trick that I have found is to use a spacer between the fan and magnet.

Hey john - do you have a pic of this? I thought the usual thing to do was to attach the magnet to the centre of the fan.

Don't bother with the speed regulator from Maplin, waste of money.

Did it not work? I'd nearly be tempted to take it off you if you don't want it.

[johnrm]

The speed controller worked, but this was not my sticking point.
The magnetic field from the magnet I was using was interfering with the fan motor - the fan would soon sometimes, but was inconsistent.
I used a bottletop as a spacer.
The trick then is balancing this which takes time and patience.
Once you have this balanced, then add the magnet being careful to keep our balanced...

This now works really well.
The trick is to speed it up to get started, then drop the speed to the desired once you have a small vortex.
I might revisit with Epoxy resin or Sugro.
Keeping an eye out for a project box.
What I am using right now cost Eur3 in total, that was for the speed control (100k potentiometer) on eBay.
The Maplin item works but I manage without.

[johnrm]

I thought you were up and running Mr. H ?

[mr hoppy]

I am, but greed is a terrible thing!

Personally, if found the speed controller chip very handy but for the more technically minded it's probably an unnecessary expense.

[johnrm]

I thought you got one of the Maplin doo-dad's from the bearded spotty chap in Maplin.
Maybe our resident genius, Sir Will might enlighten us as to the differences in lay mans terms of variable resistor vs speed controller.

[mr hoppy]

I think Will said something before about how a variable resistor can heat up or some such. A potentiometer would have been cheaper as well.

When he was over, Brian, Eoghan's brother in Wales was recommending using a controller circuit over a pot or a variable resistor. Although being a techy he was recommending building the circuit (http://www.nationalhomebrewclub.com/forum/index.php/topic,6300.msg84004.html#msg84004) which is a bit beyond me.

[johnrm]

I thought I posted already...
Thanks for the link Mr. H, I looked through Brians link and it makes sense.
The potentiometer that I am using for the past few days runs warm to touch, so I'm guessing hot internally.
In testing the speed regulator is noisy in use, there is a whine from it.

Placing the potentiometer in contact with the flask and insulating can add temp to the flask.