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.
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
Steering Bearing For Uline Sta
Steering Bearing For Uline Stainless Steel Pallet Truck - 54 4 X 78 X 16 55mm
Chemglass Life Sciences Stir Bar, Magnetic, Egg-shaped, fits 12000mL-22000mL flask, Length x Dia. in inches: 3 x 3/4
Stir Bar, Magnetic, Egg-shaped, fits 12000mL-22000mL flask, Length x Dia. in inches: 3 x 3/4. Egg-shaped magnetic stirring bar provides its own pivot point without separate ring or abrupt change in contour. Designed for use in round bottom vessels, it is shaped to spin freely, unrestricted by the vessel contour. Manufactured with FDA-grade and USP Class VI PTFE.SEE CG-2005-20 FOR STIR BAR KIT
Sigma Aldrich Fine Chemicals Biosciences SpinbarR disposable magnet
for single-use application where efficiency and cross-contamination are a concern. Alnico V magnet.
Perkin Elmer US LLC High Temperature Platinum Stirrup Kit - Qty. 4
These pans ship with the PYRIS 1 TGA High Temperature Furnace Kit.
Andwin Scientific STIRBARS MICRO 1.5MMX8MM 12/CS
The Micro PTFE Stir Bars measure 8mm x 1.5mm (5/16 in. x 1/16 in.). This product is sold in a case of 12.
Ace Glass, Inc. Stirbar, PTFE, round with x top, 10mmdia x 8mmh
Stirbar, PTFE, round with x top, 10mmdia x 8mmh
Cole-Parmer Mono-Mold Standard Stir Bar with Spinning Ring, 1"L x 3/8" dia
Mono-Mold magnetic stir bars are the standard all-purpose stir bar. Available with or without spinning rings; rings reduce contact area between stir bar and vessel, reducing friction and noise.