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™ PTFE Micro Magnetic Stir Bar
Designed for the smallest containers. Fisherbrand™ PTFE Micro Magnetic Stir Bar are autoclavable.
Fisherbrand™ PTFE Magnetic Stir Bar, Cross-shaped
Use with containers, vessel, stirrers, and stirring hot plates. The PTFE-coated magnet stirrers are stable for many general purpose applications. The bars are cross-shaped for improved stirring action.
Fisherbrand™ PTFE Magnetic Stir Bar, Cross-shaped
Use with containers, vessel, stirrers, and stirring hot plates. Fisherbrand™ PTFE Magnetic Stir Bar, Cross-shaped, offer improved stirring action.
Fisherbrand™ PTFE-Coated Rare Earth Core Stir Bars, Elliptical
Use for significantly increased magnetic strength and resistance to demagnetization. Rare earth stir bars are easily identified by a chemically inert carbon black spot.
Fisherbrand™ PTFE Magnetic Stir Bar, Cross-shaped
Use with containers, vessel, stirrers, and stirring hot plates. The PTFE-coated magnet stirrers are stable for many general purpose applications. The bars are cross-shaped for improved stirring action.
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 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.
Fisherbrand™ Cylindrical PTFE Stir Bars
Provides stable stirring action. Fisherbrand™ 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.
Cowie Technology™ Box Set of 22 Cylindrical and Removable Ring PTFE Stir Bars
Cowie Technology™ Box Set of 22 Cylindrical and Removable Ring PTFE Stir Bars includes an assortment of useful Cylindrical and Removable Ring Stirrer Bar sizes in a reusable container.
Fisherbrand™ Glass-Encased Stir Bar
Use with very abrasive media that may erode PTFE. The glass-encased magnetic stir bar is cylindrical for a wide variety of uses.
Fisherbrand™ PTFE Wing Stir Bars
Provides stable stirring action. The PTFE wing stir bars are effective in small tapered and round bottom test, centrifuge, and sample tubes.
Fisherbrand™ PTFE Magnetic Stir Bar, Single-sided crosshead
Designed for use with tube-like containers yet very effective as general stirrers. The PTFE-coated magnet stirrers include a crosshead on one side of the stirrer.
Thermo Scientific™ Nalgene™ Suspended Magnetic Stir Bars
Use these suspended magnetic stir bars for constant low-speed stirring action in tissue culture applications.
Fisherbrand™ Tube-Shaped Stirrer Bars
Designed for use with 10mm standard cuvettes. Fisherbrand™ Tube-Shaped Stirrer Bars are isostatically molded in pure FDA-approved PTFE plastic.