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 SpinbarR magnetic stirring
1 of each of blue red and yellow 8 x 1.5Amm 5 x 2Amm 7 x 2 mm 10 x 3Amm.
Electron Microscopy Sciences Rubber Policeman | 12/Box
Policeman is rubber cover to fit 5mm rods. The sealed end is cut at an angle to help stir at the bottom of container.
Chemglass Life Sciences Chemglass Stir Bar Retriever, PTFE, 350 x 10 mm (CG-2015T-03)
PTFE stir bar retriever designed to safely recover magnetic stir bars from reaction vessels and laboratory glassware. Molded in pure, FDA-approved PTFE for chemical inertness, the retriever is autoclavable and fitted with a strong magnetic tip for reliable pickup.
- Material: PTFE.
- Length: 350 mm.
- Diameter: 10 mm.
- Magnet options: Alnico V or rare earth.
- Autoclavable for laboratory sterilization.
- Designed for retrieval of magnetic stir bars from vessels.
Cole-Parmer Bel-Art Stir Bar Retriever, Flexible PTFE; 14-3/4" Long
Easily retrieve stir bars without spills or possible breakage. The alnico V magnet is completely enclosed in PTFE.
Analytical Sales & Services Well Tray Loaded with 8x30 Shell Vials, with 99685 Silicone Cap Mat, and 13258 Stir Bars
Well Tray Loaded with 8x30 Shell Vials, with 99685 Silicone Cap Mat, and 13258 Stir Bars
Electron Microscopy Sciences Veco Parallel Bar with Handle Grid R300, Copper
Veco Grids offer superior handling characteristics. Plus, with a 0.8 mil thickness, Veco Grids are the most rigid grids available. 3.05 mm diameter.
Material: Copper
Pitch: 85 µm
Hole: 45 µm
Bar: 38 µm