Stirology 101: Viscous Liquids
What are the liquid viscosity limitations of 2mag stirrers?
2mag stirrers are powerful and generally capable of successfully stirring viscous liquids. The volume/rpm maximum specifications for each 2mag stirrer are rated for a liquid viscosity up to about 500 cps. 2mag stirrers are definitely strong enough to stir thicker substances, including the Large Volume & Industrial Stirrers. For example, glycerin and motor oil @ room temperature (i.e., @ about 1,000 to 2,000 cps).
However, the 'stirring effect' is usually noticeably diminished starting at about 2,000-3,000 cps (i.e., honey or corn syrup @ room temperature) and is further lost from that point simply due to the thickness of the substance itself. Imagine yourself stirring molasses (i.e., @ about 5,000 to 10,000 cps)—or better yet brownie mix—with a spoon. Because the liquid is so viscous, the only place the liquid is effectively stirred is where it is in direct contact with the spoon. In other words, although the 2mag stirrer itself may be able to handle a certain viscosity, the liquid acts as its own limitation.
It is important to remember that the unique attributes of each application—such as the vessel shape, material, and thickness; the distance between the vessel and the stirring platform; or even the surrounding temperature—will play a role in stirring performance. Also, the type of stirring bar can also be a contributing factor in the success (or failure) of stirring viscous liquids. In some cases, a rare earth stirring bar may not only be advisable—but be required—to achieve the desired stirring effect.
If you plan to stir viscous liquids with the Small Volume & Cuvette Stirrers, then we recommend consulting with a 2mag Team Member before making a purchase to ensure that your expected results can be achieved.