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.
Electron Microscopy Sciences Spinbar Circulus™ Dumbbell Stiriing Bar 32mm White
These magnet stirring bars provide strong turbulence at relatively low speeds, offering reduced surface contact and excellent centering characteristics, particularly in vessels with convex bottoms. Ideal for 'problem' liquids, highly viscous mixtures and metal particles in fluid. All sizes have solid PTFE end disks 20 mm (.79”) in diameter. Bar diameter is 8 mm (.315”).
Color: White
Electron Microscopy Sciences Sterile Petri Dish 60x9 mm, 12 ml, 50x8 mm
Our Petri Dishes are available in a variety of shapes and sizes for use in routine procedures and with automated equipment. Economical, optical clarity, dishes are precision-molded from biomedical grade polystyrene so cultures are clearly visible without distortion. Dishes are packaged 20 each in sturdy polyethylene sleeves. These dishes are not recommended for tissue culture application, due to non treated by "corona effect". Made of polystyrene. Box type dish with tight lid ideal for culturing of mycobacteria aerosol testing, membrane filter and immunodiffusion.
Volume: 12 ml
Size: 50 x 8 mm
Sterile: Sterile
Chemglass Life Sciences Stir Bar, Micro, Magnetic, PTFE, Length x Dia. in mm: 2 x 2
Stir Bar, Micro, Magnetic, PTFE, Length x Dia. in mm: 2 x 2. Micro PTFE stir bar for the very smallest containers. Manufactured with FDA-grade and USP Class VI PTFE.SEE CG-2003-50 FOR STIR BAR KIT
Sigma Aldrich Fine Chemicals Biosciences SpinbarR magnetic stirring
Very small efficient stirring bars. Ideal for vials micro test tubes centrifuge tube mixing etc.PTfE(R) PTfE coatedALNICO V coated magnet
Sigma Aldrich Fine Chemicals Biosciences Magnetic Stir Bar round wh
The ALNICO magnetic stir bar withstands temperatures up to 250C making them suitable for use with both unheated and heated stirrers. Low friction octagon shape with a center pivot ring helps create a strong mixing vortex even with more viscous SOLUTIONons