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 PTFE TURBO STIRBAR CYLD 100/PK
NC0996444 PTFE TURBO STIRBAR CYLD 100/PK
Electron Microscopy Sciences Stirring Rod PTFE with Steel Core, 350 mm, 6 mm diameter
Steel core can be bent into a permanent shape, rods are inert and will not scratch, use up to 280 degree C, rod OD: 6 mm.
OAL: 350 mm
Rod: 6 mm
Foxx Life Sciences Borosil Reusable Solid Stirring Rods, Extra Wide Polished Glass Stirrers, 9mm x 255mm (Large Length), 20/CS
Borosil Polished Glass Solid Stirring Rods are constructed from smooth, low-expansion, low-extractable borosilicate glass. Their mechanical strength, excellent heat resistance, and outstanding chemical compatibility make them the perfect general use stirrer. Borosil Glass Stirrers are avaialble in two widths: 7mm and Extra-Wide 9mm. Each width is Avail. in four lengths, from the Short 150mm to the Extra Large 305mm. In collaboration with Borosil Glass Works, Foxx Life Sciences is proud to bring the outstanding quality of Borosil Type 3.3 Borosilicate glassware to North America for the first time. Manufactured from the same USP Type 1 borosilicate glass that North American scientists have come to trust, Borosil Laboratory Glassware offers unparalleled mechanical strength, clarity, and reliability at competitive prices. And thanks to a unique annealing process, Borosil Glassware is stress-free and incredibly resistant to thermal shock.