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.
V&P Scientific Inc STIR ELEMENT, CYLINDER, Stainless Steel, Parylene C Coated, Used in Microplates, Tubes/Vials, 1000/pack
STIR ELEMENT, CYLINDER, Stainless Steel, Parylene C Coated, 2.0mm Diameter, 4.8mm Length, 200°C Max Operating Temp for Coating, Used for Parallel Synthesis/Reaction Optimization, (1000/Pack)
Chemglass Life Sciences Stir Bar, Magnetic, Triangular, PTFE, 35mm L X 9mm Diameter
Stir Bar, Magnetic, Triangular, PTFE, 35mm L X 9mm Diameter. Effective for dissolving solids and mixing sediments in a flat bottom container such as a beaker or Erlenmeyer flask. Manufactured with FDA-grade and USP Class VI PTFE.
Electron Microscopy Sciences 18 Polygon Spin Bar Assortment Box
18 Polygon stirring bars: PTFE. consists of 2 each: 10mmx6mm, 15mmx6mm, 20mmx7mm, 25mmx8mm, 30mmx8mm, 40mmx8mm, 50mmx8mm, 60mmx8mm, 80mmx10mm.
Cowie Technology Corporation MICRO STIRBAR 3MM L 3MM D
This item has a minimum order quantity of 96 per supplier requirements. Stirbar, micro, length 3 mm, diameter 3 mm
Cowie Technology Corporation MICRO STIRBAR 3MM L 3MM D
This item has a minimum order quantity of 96 per supplier requirements. Stirbar, micro, length 3 mm, diameter 3 mm
Cowie Technology Corporation OVAL STIRBAR 70MM L 20MM D
This item has a minimum qty of 11 per supplier requirements.
OVAL STIRBAR 70MM L 20MM D
Research Products International Corp Octagon Magnetic Stirring Bar, 1 1/2x5/16
Octagon magnetic stirring bars with integral pivot ring are the most commonly used shape. Alnico magnet is encapsulated in FDA Grade, USP Class VI Teflon PTFE low friction coating; durable and inert. The interrupted profile provides greater surface area and added turbulence when compared to the smooth surface of cylindrical bars. Pivot ring aids in reducing friction and chattering . Stirring bars are autoclavable.