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.
Cowie Technology Corporation MICRO STIRBAR 6MM L 3MM D
This item has a minimum order quantity of 159 per supplier requirements. Stirbar, micro, length 6 mm, diameter 3 mm
Cowie Technology Corporation OCTAHEDRAL STIR 13MM L 8MM D
This item has a minimum order quantity of 152 per supplier requirements. Stirbar, octahedral, length 13 mm, diameter 8 mm
Cowie Technology Corporation TRIANGULAR STIRBAR L25MM D8MM
This item has a minimum order quantity of 96 per supplier requirements. Stirbar, triangular, length 25 mm, diameter 8 mm
Cowie Technology Corporation GIANT PLAIN STIR L108MMD27MM
This item has a minimum qty of 5 per supplier requirements.
Stirbar, giant plain, length 108 mm, diameter 27 mm
Cowie Technology Corporation CROSS STIRBAR 50MM L 15MM D
This item has a minimum qty of 17 per supplier requirements.
Stirbar, cross, length 50 mm, diameter 15 mm
Cowie Technology Corporation MICRO STIRBAR 30MM L 3MM D
This item has a minimum order quantity of 64 per supplier requirements. Stirbar, micro, length 30 mm, diameter 3 mm
Cowie Technology Corporation MICRO STIRBAR 5MM L 2MM D
This item has a minimum order quantity of 124 per supplier requirements. Stirbar, micro, length 5 mm, diameter 2 mm
Hach Company Stir Bar, Magnetic, Plus Shape, 1-1/2"
This magnetic stir bar adds speed and efficiency to your mixing requirements. The “+” shape creates a deep vortex and provides stable, quiet operation.
