Stirring Bars and Rods
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.
Fisherbrand™ Cylindrical PTFE or Glass Stir Bars
Alnico V magnet core encapsulated by PTFE or glass . Fisherbrand™ Cylindrical PTFE or Glass Stir Bars are autoclavable.
Fisherbrand™ Plain PTFE Stir Bars
Provides stable stirring action. Fisherbrand™ Plain PTFE Stir Bars provide greater turbulence than cylindrical stir bars.
Fisherbrand™ Oval PTFE Stir Bar
Provides stable stirring action. Fisherbrand; Oval PTFE Stir Bar povides optimal turbulence for round-bottom flasks and containers.
Azlon™ Cylindrical Stirrer Bar
Available in a range of lengths. Azlon™ Cylindrical Stirrer Bar is suitable for a wide range of flat bottomed containers.
Fisherbrand™ PTFE Stir Bars with Pivot Ring
Provides stable stirring action. Fisherbrand™ PTFE Stir Bars with Pivot Ring are ideal for containers with uneven or unusual bottom surfaces and shapes.
Azlon™ Magnetic Retrievers for Stirrer Bars
Retrieve stirrer bars from sensitive liquids with these magnetic retrievers. Azlon™ Magnetic Retrievers for Stirrer Bars feature magnets permanently embedded in a PTFE rod.
BRAND™ PTFE Magnetic Stirring Bars, Cylindrical Shape
Manufactured from PTFE. BRAND™ PTFE Magnetic Stirring Bars, Cylindrical Shape are suitable for universal applications. Rounded, smooth surface provides effective stirring action.
Fisherbrand™ PTFE Micro Magnetic Stir Bar
Designed for the smallest containers. Fisherbrand™ PTFE Micro Magnetic Stir Bar are autoclavable.
Fisherbrand™ Stir Bar Box Set, Cylindrical
Provides general purpose stirring for a wide variety of applications. Fisherbrand™ Stir Bar Box Sets, Cylindrical are isostatically molded in pure, FDA-approved PTFE plastic.
Fisherbrand™ Plain Economy PTFE Stir Bar
Provides stable stirring action. The plain economy PTFE magnetic stir bar work within a wide range of conditions, low prices from high-volume manufacturer.
Cowie Technology™ Cylindrical PTFE Stir Bars
Provides stable stirring action. Cowie Technology™ Cylindrical PTFE Stir Bars are a popular general-purpose stirrer for a wide variety of applications.
Fisherbrand™ Triangular PTFE Stir Bars
Particularly effective for dissolving solids and mixing sediments due to scraping-like action on the base of the container. The triangular PTFE stir bar provides stable stirring action for flat-bottom containers.
Fisherbrand™ Tapered PTFE Stir Bars
Provides similar action as oval or pivot ring stirrers. Cowie Technology™ Tapered PTFE Stir Bars are stable and autoclavable for a wide variety of uses.
Azlon™ Pivot Ring Magnetic Stirrer Bar
Constructed of magnetic PTFE. Azlon™ Pivot Ring Stirrer Bar includes a central pivot ring that ensures efficient spinning even on curved or uneven bases.
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Fisherbrand™ Octahedral PTFE Stir Bar
Provides stable stirring action. These PTFE magnetic stir bars are autoclavable and include a pivot ring. The flat surfaces provide a great mixing action.