LABALPHA6Pcs PTFE Magnetic Stirrer Mixer Stir Bar, Magnetic Stir Bar 10mm/0.39 inch

These work great for a magnetic stirrer

I have a Corning mixer/stirrer that I bought these for and they work perfectly in them. Only tested on thinner solutions so something that is thicker might be a little trickier with these.

Other brands I've tried were very unbalanced and would spin off at higher speeds. These are mostly well balanced and spin up to higher speeds effectively.

I used these to stir a very visqus liquid while using the hot plate on and they work really well. I got the small sided ones and they work great for small applications.

I use my magnetic stirrer in homebrewing beer. It’s a big and powerful one that I made myself and use to stir up liquids up to 6 gallons (23 liters) in glass carboys and buckets. It’s important that the magnetic stir bars are easy to sanitize to prevent potential infection and PTFE is a good material for this – it’s inert to most sanitizers and can be boiled. I found that the length of the stir bar has a very big effect on performance. Using a long stir bar (e.g. 60mm) to stir a large volume of 20 liters or more was not very effective – it would become unstable and shake off the stirrer. I found that a 40mm stirrer was optimum for almost any volume being stirred.Some of my other stir bars had a raised rib around their center. This meant that the stir bar would have point contact at its center with the bottom of the vessel – which should make it easier to spin and be quieter. These stir bars from LabAlpha did not have this rib and so they would make contact with the bottom of the vessel along their length. See the photo for details – note the slight difference in length despite both being labeled as 40mm. I did some tests to compare the two types and found that both stir bars seem to perform much the same and generated a large vortex in a 2,000mL flask without the stir bars coming loose and flying off the stirrer magnet. I felt that the LabAlpha was perhaps a bit quieter.These stir bars from LabAlpha work well and are available at a good price.

The media could not be loaded. These work perfectly with my stir plate for making fermentation yeast starters and should work perfectly with most all liquids of varying viscosity and PH.The 33mm bars worked good for the 4 to 5 inch (100 to 125mm) bottom diameter beaker and flask that I use.The low friction PTFF coated magnet bars spin smoothy and I had no problems with the magnets spinning poorly even at high rpm,Six bars at this price is a good deal. Glad I found them.

I ordered the largest size, which is his set of LABALPHA 6Pcs PTFE Magnetic Stirrer Mixer Stir Bar, Magnetic Stir Bar 50mm/1.96 inch. It is for my coffee stir replacement, but I didn't realize that it only works with certain size, and this size is just too big. However, that is my fault. The magnetic stir bars seem to be really sturdy, and sufficiently coated. I thought they were a bit expensive at around $18 for six, so around 3 dollars for a piece of magnet.

There isn’t a lot to say about these. They are pretty straightforward. I got the largest ones to use with my magnetic hot plate to stir pigments for making paint. They work as they should. I didn’t find them too expensive and was glad they come in a set of 6.