Build a magnetic stirrer ?

[Smudger]

Hi all. I would like to give this a try. I have the components : motor,magnets etc, but my lash-ups don't work. Has anyone looked inside one of these devices?
I would welcome advice on the layout of the magnet/s inside the base.
And, is the stirrer bar a magnet, or simply a steel bar?
All information gratefully received.

 

[Dave Parker]

My Sidekick processor uses a "magnetic pill" stirring system, it is a iron pill that is activated when you start the processing, that spins the pill to keep the chems mixed, pretty simple system. You might get a hold of the guys at Phototherm, as they use this type of stirring system in many of their products.

http://www.phototherm.com

Dave

 

[avandesande]

the stir bar is a teflon coated magnet.

 

[Dave Parker]

the stir bar is a teflon coated magnet.

Could be, I thought they told me the one in my processor is iron, alls I know is it works.

Dave

 

[L Gebhardt]

Last I looked you could get magnetic stirring hot plates for dirt cheap on ebay.

 

[avandesande]

I was really talking about the ones you generally buy from chemical supply. Not sure about yours....

 

[glbeas]

The stirrers use a strong bar magnet on a rotor under the plate, usually one of the super strong exotic alloys. The stir bar is a smaller but similar magnet encased in plastic.

 

[25asa]

What would one have to do to use a kitchen blender?

 

[glbeas]

You could engineer a bar to fit the motor shaft and a plate to sit on top of the unit. Most blenders go so fast though the bar would not be able to couple to the base magnet even at the lowest speed. It would likely just sit and vibrate.

 

[JLMoore3]

Why not just use a kitchen blender for your mixing? I've been using one dedicated to the darkroom- works for me.

 

[vet173]

The problem with a blender that I see is that you would be introducing a lot of air into the solution. Not good with stuff that oxidises.

 

[pnance]

I have two stirrers. One has a bar magnet which is hard to control, it either spins too fast and or loses control of the stirring magnet.

The other is a Corning heater/stirrer, the magnet is a round device like a donut, better balancing, and has very good slow speed control.

 

[Smudger]

Thanks to all who responded. I will continue my experiments..

 

[donbga]

Thanks to all who responded. I will continue my experiments..

I have to ask why? High quality used stirrers can be purchased on e-bay. Spend your time making photographs.

Don Bryant

 

[Gerald Koch]

I have two stirrers. One has a bar magnet which is hard to control, it either spins too fast and or loses control of the stirring magnet.

This problem can be remedied by the choice of the proper size bar. One size does not fit all containers.

 

[Gerald Koch]

My stirrer has a very thin aluminum top surface in order to get the two magnets as close together as possible. Another design consideration is to get the internal bar magnet properly centered on the motor shaft so that there is no vibration. The motor must be chosen for its torque and maximum speed. A lot of design problems. Considering they are not that expensive I would just buy one wither new or used.

 

[Gerald Koch]

My concern in using a blender is their small capacity and mixing too much air into solutions.