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.
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.
Azlon™ Micro Magnetic Stirrer Bar
Use these bars in for a variety of stirring applications. Fisherbrand™ Azlon™ Micro Magnetic Stirrer Bars are ideal for small vessels, test tubes and vials.
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Fisherbrand™ PTFE Micro Magnetic Stir Bar
Designed for the smallest containers. Fisherbrand™ PTFE Micro Magnetic Stir Bar are autoclavable.
Fisherbrand™ PTFE Magnetic Stir Bars with Pivot Ring
Used in containers with bases that are slightly curved or uneven.
Azlon™ Cylindrical Stirrer Bar
Available in a range of lengths. Azlon™ Cylindrical Stirrer Bar is suitable for a wide range of flat bottomed containers.
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.
BRAND™ PTFE Magnetic Stirring Bars Retriever
Manufactured from PTFE. BRAND™ PTFE Magnetic Stirring Bars Retriever has a magnetic core that is fully sealed to prevent leeching.
BRAND™ PTFE Magnetic Stirring Bars with Pivot Ring, Cylindrical Shape
Manufactured from PTFE. BRAND™ PTFE Magnetic Stirring Bars with Pivot Ring, Cylindrical Shape are for use with vessels that have slightly uneven bottoms. Pivot ring reduces the contact surface and enables the stirrer to adopt the optimum stirring position.
Azlon™ Oval Magnetic Stirrer Bar
Use these bars in for a variety of stirring applications. Azlon™ Oval Magnetic Stirrer Bars are ideal for round bottomed flasks.
SI Analytics™ PTFE Coated Magnetic Stirrer Rod Set
SI Analytics™ PTFE Coated Magnetic Stirrer Rod Set is designed for use in standard applications.
Fisherbrand™ Magnetic Stirring Bars
Stirbar assortments come in a convenient storage box. Fisherbrand™ Magnetic Stirring Bars contain PTFE encapsulated Alnico magnets and come in various sizes.
Fisherbrand™ Octagon Spinbar™ Magnetic Stirring Bars
Octagon magnetic stirring bars with integral pivot ring are the most commonly used shape for stirring small volumes in vessels such as vials, tubes and gradient makers.
