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.
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.
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™ 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.
Fisherbrand™ Solid PTFE Stirring Rod
Chemically resistant, inert and leak-free
Fisherbrand™ Solid PTFE Stirring Rod
Can be used in temperatures up to 280°C (540°F). The PTFE stirring rod has a solid PTFE core. These rods are chemically resistant, inert, and leak-free.
BRAND™ AR-GLAS™ Stirring Rods
Constructed of AR-GLAS™. Tubes are fused closely at both ends.
Fisherbrand™ PTFE Stir Bar Retriever
Use to retrieve stir bars from mixing containers. The PTFE stir bar retriever is chemically resistant, inert, and leak-free. Uses Alnico V magnets at its core.
Fisherbrand™ PTFE Micro Magnetic Stir Bar
Designed for the smallest containers. Fisherbrand™ PTFE Micro Magnetic Stir Bar are autoclavable.
Fisherbrand™ Oval PTFE Stir Bar
Provides stable stirring action. Fisherbrand; Oval PTFE Stir Bar povides optimal turbulence for round-bottom flasks and containers.
Fisherbrand™ PTFE Magnetic Stir Bars with Pivot Ring
Used in containers with bases that are slightly curved or uneven.
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.