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, NdFeB Magnet, 42MGO, PEEK Encapsulated, Used in Bottles, Tubes/Vials, 10/pack
STIR ELEMENT, CYLINDER, NdFeB Magnet, 42MGO, PEEK Encapsulated, 11.5mm Diameter, 23.1mm Length, 150°C Max Operating Temp for Magnets
Cole-Parmer Egg-Shaped Stir Bar, 2-1/2" L x 3/4" Dia; 1/Pk
Egg-shaped stir bars have oval magnets—ideal for use in round-bottom flasks. Shape conforms to flask bottom and ensures complete mixing.
Cole-Parmer Essentials PTFE Stir Bar, Plain, 25 x 10mm
These PTFE stir bars feature a slimmer profile and larger length to diameter ratio.
Electron Microscopy Sciences Spinbar Circulus™ Dumbbell Stiriing Bar 32mm Blue
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: Blue
Electron Microscopy Sciences Spinbar Circulus™ Dumbbell Stiriing Bar 52mm 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
Enterprise Technology Solutions Absorbent Specialty Products Flood Barriers,4 Gallon/32 lb Cap,5'Lx3.5"H,16/CT,Black
Flood Barriers absorb, contain and divert problem floodwater to help protect your property from the dangers of flooding. They activate when wet and require no sand. Each 5' long barrier absorbs 4 gallons of water, swells to 32 lb. and expands to 3.5" high in 10 minutes. This compact, lightweight flood control is quick and easy to deploy. Flexible design conforms to shapes and can also be dragged for easy maneuverability. Inner absorbent turns to gel and creates a barrier. Dual-lobe chamber prevents rolling out of position. Leave in place for ongoing protection. Setup requires no additional tools or supplies. Barriers are safe, nontoxic and nonhazardous. Discard into regular trash when you no longer need them.