• Members of the previous forum can retrieve their temporary password here, (login and check your PM).

DIY Magnetic Stirrers and Hotplates

Migrated topic.
It looks like the simplest, most common way to construct one is to glue what they call a rare earth magnet, from a hard drive, onto a computer fan and find a way to power it and control speed (the second video that builds one from scratch is a cheap alternative if you don't already have these items ready on hand). Throw a thermoelectric cooler on top as a heating element if so desired.

[YOUTUBE]

Here's a video for the first one in the OP:
[YOUTUBE]


I still think the lego method is the coolest way, but I wonder if the heating element could be implemented without melting the legos.
 
Hot-plate is kind of bunk.

The stirrer's look decent.

Honestly though, if your going to spend 30 on a stirrer and like 15 on a dodgy hot-plate you might as well buy a used real hot-plate imo. Not trying to knock innovation! Just throwing it out there.
 
Metta said:
Honestly though, if your going to spend 30 on a stirrer and like 15 on a dodgy hot-plate you might as well buy a used real hot-plate imo. Not trying to knock innovation! Just throwing it out there.
Click to expand...

The whole thing with the stirrer and hotplate is less than $30. SWIM probably wouldn't need temps much higher than those of this hotplate. Whether it's found useful for chemistry purposes or not, the temp should be perfect for making lattes, so there's always that:wink:

In any case the I'm most fond of the lego one, and I've already got all the parts besides the motor and power-source on-hand.
 
I made this stirrer out of an old cd player. I mounted a fan on the vibration isolator that the laser was mounted to. Used the power button on the front and wired in a speed controller. The second pic shows the adjustment knob of the speed controller and a cool vortex in the jar.

It was a lot of fun to make. That being said,it works ok for small jobs and doesn't for large or thick jobs.
If you can get a cheap one BUY it. The hotplate would be very useful also.
CHAOS
 

Attachments

  • 100_2650.JPG
    100_2650.JPG
    520.9 KB · Views: 0
  • 100_2652.JPG
    100_2652.JPG
    686 KB · Views: 0
How did you wire in the speed controller? Swim used to have one of these for yeast but could never control the speed.
 
ragabr said:
Another instruction set for building your own.
Click to expand...

It seems that to build an overhead stirrer and a separate hotplate would be much more practical. Magnetic stirrers are very limited in respect of volume and viscosity of the medium they can stir. Swim's professional magnetic stirrer was useless for stirring 3 l of thick aqueous solution during an STB extraction.

It is also a problem to combine a magnetic stirrer and a hotplate. Excessive heat can destroy a permanent magnet and over heat wiring of your electric magnet.

Any variable speed rotary tool (Dremel?) would do. With sufficient power you can stir almost anything. Of course you would need a lab stand to fix it and a non-reactive shaft with a propeller to stir your liquid.
 
I once built a homemade magnetic stirrer for propagating yeast cultures to be used in brewing large batches of beer. It's been a while, but I'm pretty sure the instructions I (more or less) used can be found here. It works pretty well with 500-1000ml of thin liquid, but did almost nothing for a decent sized STB or anything much thicker than the consistency of water. I've since purchased a used lab-grade Corning hotplate/stirrer from eBay and it was the best investment I've made since picking up my 1000ml sep funnel. It's certainly not the cheapest way to go and there's no DIY fun involved, but it's extremely reliable even for thick soupy mixtures of 2L or more. The stirrer can virtually create a vortex in mud and it heats up to 550C :shock:. If I remember correctly it cost a little over $100.

Don't get me wrong, I absolutely love DIYers/'makers' and amateur innovation. But for my purposes the professional-grade stirrer was necessary to get the job done effectively.
 
hahahha omfg!!this lego stirrer seems to work better than my real magnetic stirrer.:shock:
you can find teflon-covered magnets to put into the jar so they wouldnt' encrust and they're almost inerts to most of chemicals
 
Back
Top Bottom