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Magnetic Stirrer V 2.0

A project log for DIYbio Lab

We're building a DIYbio lab, including custom-building the equipment.

ProgressTHProgressTH 07/20/2019 at 07:140 Comments

July 20, 2019 | ProgressTH Version 2 of our magnetic stirrer is now on Thingiverse

It is a completely new design, using a 12V DC motor with a cheap motor speed controller, a 13mmx2.5mm neodymium (x6) rotor and a much larger, sturdier platform for mixing up to 6L of liquid. 

The support structure creates continuous support from the platform, through the support brackets, to 4 inner feet at the bottom of the case, and onto whatever surface you're operating the stirrer on. This allows it to hold a lot of weight without the platform sagging and making contact with the magnet rotor which you want to be as close to the platform as possible without ever touching it. 

The 12V DC motor gives better speed control and overall speed creating stirring functions the computer fan can not compete with. The computer fan-based stirrer is still a super-simple and effective means of magnetic stirring, but this improved version is more powerful and more versatile. 

There are also 2 new magnetic stir bar designs pictured below (center and right) using the same 13mm neodymium magnets as the rotor — one with 2 magnets, and another with 4. 

The more volume or viscosity you're mixing or the thicker the base of your container is, the stronger the magnetic field needs to be for the rotor and the stir bar to link up when at speed. 

Finally, we've included an image of the new design (right) next to the original computer fan-based design (left) which was our very first piece of DIYbio equipment we ever made. 

What to use it for? We use it to mix hydroponic nutrients, separate tomato seeds from pulp, and process grated homemade soap into liquid soap. There's probably a lot of other applications you could use this for. 

!!!Just remember!!! our stir bars are 3D printed. They are not food grade, they are not rated for corrosive chemicals, and could even have little plastic splinters come loose. Keep this in mind when using them to stir. 

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