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.
Ace Glass, Inc. Stirbar, PTFE, egg shape, 25.4mmx12.7mm
25.4mm x 12.7mm egg-shaped PTFE magnetic stir bar which provides a pivot point without a separate ring or abrupt change in contour. Designed to be used with round bottom flasks and DynaBlocs.
Ace Glass, Inc. Stirbar, PTFE, octagonal, 28.6mmx8.0mm
28.6mm X 8.0mm PTFE, octagonal stirbar with pivot ring in center.
Cole-Parmer DWK Life Sciences (Kimble) Stir Rod, Glass, 6.4 mm dia X 250 mm L, 25/pk
Manufactured with borosilicate glass with rounded annealed ends. Stir rods are highly chemical resistant and withstands temperatures to 400° F (205°)C. Autoclavable.
Chemglass Life Sciences Stir Bar, Micro, Magnetic, PTFE, Length x Dia. in mm: 2 x 2, Bulk Packed
Stir Bar, Micro, Magnetic, PTFE, Length x Dia. in mm: 2 x 2, Bulk Packed. Micro PTFE stir bar for the very smallest containers. Manufactured with FDA-grade and USP Class VI PTFE.
Chemglass Life Sciences Stir Bar, Micro, Magnetic, PTFE, Length x Dia. in mm: 3 x 3, Bulk Packed
Stir Bar, Micro, Magnetic, PTFE, Length x Dia. in mm: 3 x 3, Bulk Packed. Micro PTFE stir bar for the very smallest containers. Manufactured with FDA-grade and USP Class VI PTFE.
Chemglass Life Sciences Stir Bar, Magnetic, PTFE, Turbo, Rare Earth, Elliptical, 70 x 28mm
Exceptional strength coupled with almost total resistance to demagnetisation. Identified by an inert carbon black spot.
Azzota Corp Magnetic Stirring Bars - Z Type, 7mm Length, Dia. 3mm
Magnetic stirring Bars - Z type, 7mm length, Dia. 3mm
Cole-Parmer Essentials PTFE Stir Bar, Plain, 25 x 10mm
These PTFE stir bars feature a slimmer profile and larger length to diameter ratio.
Research Products International Corp Spinbar Magnetic Sink Strainer, Blue
The Spinbar Magnetic Sink Strainer provides an innovative solution to a common laboratory inconvenience. Prevents magnetic stirring bars from accidentally slipping into the drain when cleaning beakers or cylinders. Flexible chemical resistant strainer has four strong magnets that attract and hold stirring bars. The strainer is designed with long slits that allow unobstructed drainage of fluids. Strainer remains securely in place and fits a variety of sinks. Flat edge allows strainer to be placed near the sink wall.
Research Products International Corp Flea Micro Magnetic Stirring Bar, 10 x 3 mm
Micro (Flea) magnetic stirring bars are designed for stirring small volumes in vessels such as vials, tubes and gradient makers. Particularly useful for environmental testing and life science applications in which small sample volumes need to be prepared and evaluated.
Analytical Sales & Services Stir Bars 1.6X4.8MM, Parylene-Encapsulated Stainless Steel, Non-Magnetic, 1000 Units
STIR BARS 1.6X4.8MM 1000CS stir bars are engineered for precise agitation in photoredox and parallel synthesis systems. Made with durable parylene-encapsulated stainless steel, they are chemical resistant and non-magnetic, ensuring controlled mixing for sensitive applications. Packaged with 1000 units, these stir bars support high-throughput experiments, distinguishing themselves from others with their efficient manipulation by external magnetic forces.