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.
Hach Company Stir Bar Retriever
Polyethylene pickup rod with powerful magnet sealed in one end and hangup grip on other; 31 cm (12") long.
Med Vet International Jorvet T-Bar OB Handle, J0024T
Allows for use of both handsfor pulling. Handle 22cm L.
Ace Glass, Inc. Stirbar, PTFE, octagonal, blue, 38.1mmx8.0mm
38.1mm x 8.0mm blue octagonal PTFE stirbar with pivot ring.
PATHOLOGY INNOVATIONS The 24mm Deep Well Bar has four 24mm wells, two that are 6mm deep and two that are 9mm deep, on one-inch thick stainless steel. These bars are stored in the cryostat and serve as a powerful heat sink to rapidly freeze the block.
When using the Peters Precision Cryoembedding System, embedding is performed in wells machined into the face of one-inch thick stainless steel bars offered in various sizes. The 24mm Deep Well Bar has four 24mm wells, two that are 6mm deep and two that are 9mm deep, on one-inch thick stainless steel. These bars are stored in the cryostat and serve as a powerful heat sink to rapidly freeze the block. Add additional well bars like this one to your existing Peters Precision Cryoembedding System. The Peters Precision Cryoembedding System was designed by inventor, professor and author of frozen section literature Dr. Stephen Peters to give users more precision and control when doing a high volume of frozen section procedures. Learn how to use the system as well as advanced frozen section technique at pathologyinnovations.com.