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 Micro Stir Bar, 7 mm L x 2 mm Dia; 1/Pk
Strong alnico V magnets with one-piece coating of PTFE.
Fireflysci P68 Mixer for Semi-Micro Cuvettes (Type 9, Type 9B, Type 9BM, Type 9F, Type 9M)
Manual mixer fits any standard 10mm pathlength cuveette with a 4mm inside width• Made of clear acrylic with a straight handle, this tool is used when reactives are performed directly into cuvettes to mix added reagents. Up and down motion in cell provides complete mixing• Shaft diameter- 3.17mm (0.125 inches)
RENICK LABS LLC Disposable, Parylene-encapsulated stir bars for 8x30mm glass shell vial work, 1000/pk
Need disposable stir bars for use with 8mm glass shell vials? RL 352A stir bars are the perfect size. Parylene is vapor deposited to the surface of every stir bar ensuring the best possible encapsulation and guards against reaction interference. While the vast majority of chemical reactions do not affect the Parylene coating, extended stirring times of heterogeneous mixtures at elevated temperatures, ethereal solvents such as Dioxane and THF may cause degradation.
Electron Microscopy Sciences Rubber Policeman | 12/Box
Policeman is rubber cover to fit 5mm rods. The sealed end is cut at an angle to help stir at the bottom of container.
Cole-Parmer Micro Stir Bar, 5 mm L x 2 mm Dia; 1/Pk
Strong alnico V magnets with one-piece coating of PTFE.