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.
Cole-Parmer Starburst Magnetic Stirring Heads, 3/4" x 3/4"; 1/Pk
Stirring heads produce a large vortex for quick, efficient mixing—conserve both energy and valuable lab time. Powerful alnico V magnet is coated with PTFE for purity and excellent chemical resistance. Fully autoclavable.
Andwin Scientific SPINBAR DISP 1/2D X 1/2L
The Spinbar are disposable, multifaceted stir bars that increase turbulence relative to similar size smooth cylindrical stirring bars. This product is recommended for use in single use applications, such as mixing radioactive reagents. The stirring
Chemglass Life Sciences Agitator, PTFE, High Viscosity, 5in Diameter, Fits 19mm Shaft Size, Fits 2L-5L Reactors
Agitator, PTFE, High Viscosity, 5in Diameter, Fits 19mm Shaft Size, Fits 2L-3L Reactors. High viscosity agitator, made entirely of PTFE and glass filled PTFE, provides excellent stirring at the bottom of 2L through 3L reactors, especially when heavy slurries are being mixed. Agitator attaches to stir shaft by both a compression fitting and a glass filled PTFE safety pin. Heavy duty blades are 7mm thick. Supplied complete with one glass filled PTFE safety pin.
Electron Microscopy Sciences Micro Stir Bars, 3 x 10 mm
Coated with "PTFE" white resin. For stirring test tubes, micro-beakers, and more.
Size: 3 x 10 mm
Sigma Aldrich Fine Chemicals Biosciences Rare earth extra power stir bars oval, diam. 5 mm, L 10 mm | 3EA
Rare earth extra power stir bars oval, diam. 5 mm, L 10 mm | 3EA
Sigma Aldrich Fine Chemicals Biosciences Rare earth extra power stir bars Elliptical, diam. 14 mm, L 25 mm | 3EA
Rare earth extra power stir bars Elliptical, diam. 14 mm, L 25 mm | 3EA
Chemglass Life Sciences Chemglass Stir Bar, PTFE-Coated Magnetic Micro, 10 x 3 mm, Pack of 50 - for magnetic stirrers
Chemglass PTFE-coated magnetic micro stir bars provide reliable mixing in very small volumes. Each bar measures 10 x 3 mm and is bulk packed in a 50-piece set for convenient laboratory use. The PTFE coating meets FDA-grade and USP Class VI standards for chemical resistance and biocompatibility.
- PTFE coating with FDA-grade and USP Class VI compliance.
- Micro size: 10 x 3 mm.
- Bulk pack: 50 pieces per pack.
- Designed for use with magnetic stirrers and hot plate stirrers.
- Suitable for small-volume mixing and agitation.