Stirring Bars and Rods
Products of various sizes, shapes, and material compositions designed to aid in manual or automatic stirring of laboratory solutions. Includes glass stirring rods, magnetic stir bars, and stir bar retrievers.
What Is a Magnetic Stir Bar?
Magnetic stir bars are stirrers or stirring hotplates used with magnets to mix a liquid or solution by creating a vortex.
A number of factors affect magnetic stir bar efficiency and effectiveness, including its size, shape, and material. Sizes (L x Diameter) range from 2 x 2 mm to 159 x 27 mm and shapes include:
- Polygonal or octagonal magnetic stir bars are the most common shapes; the multiple surfaces add turbulence to the mixing action
- Elliptical or egg-shapped stir bars work especially well with round-bottom flasks
- Wedge-shaped spin bars produce more significant turbulence for dissolving salts or in samples containing sediment
- Spin bars with fins or vanes, designed for smaller vessels, tubes, or cuvettes
- Micro (“flea”) stir bars for mixing extremely small samples
What Kind of Magnet Is Used?
Stir bar magnets are typically made from Alnico, a combination of aluminum and nickel. They may also be made from Samarium cobalt, a rare earth metal that produces the stronger magnetic force needed to mix very viscous substances.
Stir bar magnets are usually encapsulated in white or colored PTFE, hard plastic, or borosilicate glass, and coatings may meet FDA grade or USP requirements. PTFE is durable, inert, and can be autoclaved. Glass-encased cylindrical magnets are useful for high-temperature applications.
How Does It Work?
During the stirring process, integral or removable pivot rings on the stir bar reduce contact with the vessel to help avoid marring plastic surfaces. Some round stir bars have slightly raised ends that create a de facto pivot point, while others have more pronounced round centers that help to keep them in motion. Stir bars may be reusable or disposable.
Magnetic stir bars may be sold individually or in magnetic stir bar kits that include multiple bars in a range of sizes.
Heidolph™ Magnetic Stirrer Accessory, Stir Bars
Stir bars for use with various Heidolph magnetic stirrers
DWK Life Sciences Kimble™ KIMAX™ Solid Rod Stirrers
Designed from Federal Specification NNN-R-560, Type I requirements
Fisherbrand™ Polygon Stir Bars
Stir bars have polygon multifaceted surfaces that add turbulence relative to similar smooth size cylindrical bars.
Fisherbrand™ Magnetic Stir Bar Six Packs
These magnetic stirring bars are the most commonly used shape.
Fisherbrand™ PTFE Disposable Stir Bars
The multifaceted magnetic stirring bar surface adds turbulence relative to similar size smooth cylindrical stirring bars.
METTLER TOLEDO Stirrer Bar for Small Titration Vessel for EVA V1/V3 KF Titrator
Elevate your analysis with our specialized accessories for the EVA Karl Fischer V1 and V3 Titrators.
Fisherbrand™ Cylindrical Spinbar Magnetic Stirring Bar
Cylindrical magnetic stirring bars offer excellent centering and smooth-running characteristics.
Velp Scientifica™ Magnetic Stir Bars
Provides stable, general purpose stirring. Velp Scientifica™ Magnetic Stir Bars fit with a range of Velp Scientifica™ stirrer units.
Thermo Scientific™ Komet Stir Bars
Generate over three times the torque of conventional stirring bars with these komet stir bars, significantly enhancing stirrer performance and versatility.
Stellar Scientific Magnetic Stir Bars with Pivot Ring, PTFE for Magnetic Stirrers and Hotplates, 50mm (2-pack)
Magnetic Stir Bars with Pivot Ring, PTFE for Magnetic Stirrers and Hotplates, 50mm (2-pack) 50mm Length x 6mm Diameter
Fisherbrand™ cuvette Stirrer
Economical disposable stirrers.
Bel-Art™ Cell Spinbar™ Stir Bar for Spectrophotometer Cells
For 10 mm lightpath spectrophotometer cells
Chemglass Life Sciences Plain PTFE Magnetic Stirring Bar, 50 x 8 mm, for Magnetic Stirrers
Plain PTFE-coated magnetic stirring bar (50 x 8 mm) for general-purpose laboratory mixing on magnetic stir plates. Its cylindrical plain profile provides effective agitation and produces increased turbulence at low speeds, while the PTFE coating offers chemical resistance and a non-stick surface.
- Plain cylindrical shape for general-purpose stirring.
- Dimensions: 50 x 8 mm.
- PTFE coating provides chemical resistance and non-stick surface.
- Produces increased turbulence at low stirrer speeds.
- Compatible with standard magnetic stir plates and laboratory mixers.
- Sold individually for easy replacement.
