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.
Sigma Aldrich Fine Chemicals Biosciences SpinbarR magnetic stir bar1EA
Leakproof seamless polished and contains a permanent Alnico V magnet. Egg-shape bar is designed especially for use in round-bottom vessels.
Electron Microscopy Sciences Spinbar Circulus™ Dumbbell Stiriing Bar 52mm White
These magnet stirring bars provide strong turbulence at relatively low speeds, offering reduced surface contact and excellent centering characteristics, particularly in vessels with convex bottoms. Ideal for 'problem' liquids, highly viscous mixtures and metal particles in fluid. All sizes have solid PTFE end disks 20 mm (.79”) in diameter. Bar diameter is 8 mm (.315”).
Color: White
Chemglass Life Sciences Stir Bar, Magnetic, PTFE, Length x Dia. in mm: 15.9 x 7.93, Length x Dia. in inches: 5/8 x 5/16
Stir Bar, Magnetic, PTFE, Length x Dia. in mm: 15.9 x 7.93, Length x Dia. in inches: 5/8 x 5/16. Octagon cross-section having a molded-in pivot ring manufactured with FDA-grade and USP Class VI PTFE. The PTFE coated Alnico magnet permits magnetic agitation without contamination.SEE CG-2001-50 FOR STIR BAR KIT
Cole-Parmer Essentials PTFE Stir Bar, Plain, 25 x 10mm
These PTFE stir bars feature a slimmer profile and larger length to diameter ratio.
Sigma Aldrich Fine Chemicals Biosciences Rare earth extra power stir bars, 3/pk
Elliptical, diam. 6 mm, L 10 mm. Stirring bars using rare earth magnets have significantly increased magnetic strength compared to those using Alnico magnets, but more importantly they are almost totally resistant to demagnetisation.
Chemglass Life Sciences Stir Bar, Micro, Magnetic, PTFE, Length x Dia. in mm: 15 x 1.5
Stir Bar, Micro, Magnetic, PTFE, Length x Dia. in mm: 15 x 1.5. Micro PTFE stir bar for the very smallest containers. Manufactured with FDA-grade and USP Class VI PTFE.SEE CG-2003-50 FOR STIR BAR KIT
Chemglass Life Sciences Stir Bar, Magnetic, Egg-shaped, fits 5mL-25mL flask, Length x Dia. in inches: 3/8 x 3/16
Stir Bar, Magnetic, Egg-shaped, fits 5mL-25mL flask, Length x Dia. in inches: 3/8 x 3/16. Egg-shaped magnetic stirring bar provides its own pivot point without separate ring or abrupt change in contour. Designed for use in round bottom vessels, it is shaped to spin freely, unrestricted by the vessel contour. Manufactured with FDA-grade and USP Class VI PTFE.SEE CG-2005-20 FOR STIR BAR KIT
Thomas Scientific Stir Bar, Cylindrical, PTFE, 15mm, Bag of 2
Produced from PTFE For the stirring of liquids on magnetic stirrers and/or hotplate stirrers Strong alloy magnets sheathed in pure white inert PTFE Supplied in polarity aligned packs to ensure maximum coupling strength Resistant to virtually all chemical attack and temperatures up to 260°C
Chemglass Life Sciences Stir Bar, Magnetic, PTFE, Length x Dia. in mm: 12.7 x 9.52, Length x Dia. in inches: 1/2 x 3/8
Stir Bar, Magnetic, PTFE, Length x Dia. in mm: 12.7 x 9.52, Length x Dia. in inches: 1/2 x 3/8. Octagon cross-section having a molded-in pivot ring manufactured with FDA-grade and USP Class VI PTFE. The PTFE coated Alnico magnet permits magnetic agitation without contamination.SEE CG-2001-50 FOR STIR BAR KIT
Chemglass Life Sciences Stir Bar, Magnetic, Egg-shaped, fits 300mL-500mL flask, Length x Dia. in inches: 1 1/2 x 5/8
Stir Bar, Magnetic, Egg-shaped, fits 300mL-500mL flask, Length x Dia. in inches: 1 1/2 x 5/8. Egg-shaped magnetic stirring bar provides its own pivot point without separate ring or abrupt change in contour. Designed for use in round bottom vessels, it is shaped to spin freely, unrestricted by the vessel contour. Manufactured with FDA-grade and USP Class VI PTFE.SEE CG-2005-20 FOR STIR BAR KIT
Cole-Parmer Large-Volume Stir Bar, 6-1/4"L x 1-1/16"dia
Use this large-volume stir bar with your large-capacity stirrers and hot plate stirrers.
Sigma Aldrich Fine Chemicals Biosciences BRAND MAGNTC STIRBAR OVAL 15MM
NC3369713 BRAND MAGNTC STIRBAR OVAL 15MM
Sigma Aldrich Fine Chemicals Biosciences CORNING MAG STIR BAR RETRIEVER
NC3848688 CORNING MAG STIR BAR RETRIEVER