Stoppers
Stoppers, also known as bungs, are used to give an airtight seal to laboratory flasks and test tubes by fitting tightly inside the neck of the container and preventing material from spilling. Stoppers can be made of glass, cork, rubber, or silicone. They are typically designed with a conical shape, but straight, flanged, and tapered options are also available.
Stoppers are the preferred choice for many applications requiring a tighter seal or a greater degree of chemical resistance. They also provide a good seal when a solution needs to be shaken or mixed without spilling. Stoppers are generally cylindrical in shape and have a tapered bottom end. They may be marked with a stopper number or size on the top and bottom diameters of the stopper. Sizing can vary among manufacturers.
Stoppers are available in a solid design or with holes known as positions placed in the top. Positions allow easy access to the material contained in the sealed vessel by pipettes, tubing, or other equipment without full removal of the stopper.
What Types of Stoppers Are Available?
• Turnover stoppers have external serrations to create an excellent internal seal combined with a flexible turnover sleeve that folds down over the container’s neck to create a double seal
• Serum bottle or vial stoppers have two or three legs with external serrations or straight sides and a flanged top to create an airtight seal
• Straight bromobutyl plug-type stoppers provide a maximum seal for vials and serum bottles with a straight-wall glass finish
• Ultra-pure, straight bromobutyl plug-type stoppers provide high chemical purity and low gas permeability. They offer excellent performance during freeze drying processes such as lyophilization, where stoppers must remain stable during transfer and sublimination phases
• Silicone recessed septa stoppers are non-toxic and have external serrations to create an effective internal seal
Cole-Parmer Solid Color-Coded Silicone Stoppers, Standard Size 9.5, Pink; 5/Bag
Silicone bubbles make these stoppers lightweight—they float on water. Withstand temperatures from –76 to 392°>F (–60 to 200°>C). Stoppers are available in 14 color-coded sizes, given in both standard and Japanese size numbers. Softness and flexibility allow stoppers to fit a range of holes. Easily make openings for glassware fit your exact specifications with the optional cork borer set. 2 bg/cs.*
Cole-Parmer High-purity silicone stopper, size 8 (41D) Pack of 5
Translucent silicone stoppers are especially suited for procedures demanding high purity, such as tissue culture work and food science applications. Food-grade quality stoppers are nontoxic, chemically inert, and resist particle buildup. Withstand repeated sterilization, as well as temperatures from –76 to 392°F (–60 to 200°C). Peak at 428°F (220°C). European size (DIN no.) is noted on stopper. FDA compliant. Autoclavable.
Accuflow Systems Saint-Gobain Silicone Stopper, Size 3, Platinum-Cured Silicone, Autoclavable
Sani-Tech silicone stopper size 3 is an ultra-pure, platinum-cured silicone closure engineered for laboratory and bioprocess applications. It offers high purity, resistance to cracking and spallation, and is fully autoclavable for sterile processing.
- Ultra-pure platinum-cured silicone.
- Size 3, suitable for carboys and solution bottles.
- Dimensions: A 0.950 in (24.1 mm), B 0.725 in (18.4 mm), H 0.982 in (24.9 mm).
- Fully autoclavable and sterilizable.
- Resists cracking and spallation, minimizes particulate release.
- Common applications include process and storage procedures and laboratory apparatus.
Grainger K4796 Silicone Round Cord 5/16 D 25 L 70A Blue
The Silicone Round Cord Metal is a silicone rubber cord with a metal core that is flexible and durable. It has a temperature range of -60°F to 500°F and comes in multiple diameters and lengths. The cord has good electrical insulation properties and high tensile strength. It is often used for applications like weatherstripping, gasketing, binding, and holding. This product can provide flexibility while maintaining shape in high heat environments. The metal core offers rigidity while the silicone exterior provides insulation against electricity, moisture, and weather.
Grainger K4796 Silicone Round Cord 3/16 D 10 L 70A Blue
The Silicone Round Cord from Grainger is a flexible, durable silicone cord that can withstand temperatures from -100 to 500°F. It has a round cross-section and comes in multiple diameters from 1/16 inch to 3/4 inch. The cord is made from platinum-cured silicone which provides excellent resistance to weathering, aging, moisture, and UV rays. With its high flexibility and temperature resistance, this silicone cord is ideal for a variety of applications including gaskets, seals, hose fabrication, and more. The cord can be cut to desired lengths.
Ace Glass, Inc. Full-length hollow glass stopper with 45/50 standard taper joint.
Full-length hollow glass stopper with 45/50 standard taper joint.
Electron Microscopy Sciences Clear Silicone Rubber Kit 1 GL
This silicone cures at room temperature with no shrinkage and offers a unique water clear see through rubber with excellent tear strength, chemical, and heat resistance.
Allow the mold to cure overnight (at least 16 hours) at room temperature (77 degree F/25 degree C) before demolding. Do not cure rubber where temperature is less than 65 degree F/18 degree C. Post curing the mold will aid in quickly attaining maximum physical and performance properties. After curing at room temperature, expose the rubber to 80 degree C for 2 hours and 100 degree C for 2 hours. Allow mold to cool to room temperature before using.
NOTE: This clear silicone will cause rubber to yellow when applying post curing. Clear silicone comes as a kit of 1 gallon (9 lb) silicone A and 1 pint (.9lb) curing agent B.
Grainger K4796 Silicone Round Cord 5/16 D 50 L 70A Blue
The Silicone Round Cord from Grainger is a flexible, durable silicone cord that can withstand temperatures from -100 to 500°F. It has a round cross-section and is available in multiple diameters from 1/16 inch to 3/4 inch. The cord comes in standard lengths of 25 feet and 50 feet and has excellent resistance to weather, moisture, and UV rays. This silicone cord can be used for a variety of applications including weatherstripping, gasketing, binding, and tying. It will not melt or burn and provides a long service life. The cord has good chemical resistance and will not mark or stain surfaces.
Alkali Scientific CellPro™ 24-Well, Silicone Sealing Mats, 50/pk, Sterile
CellPro™ 24 Well, Silicone Sealing Mats seals 24 wells at a time for minimal evaporation / sample loss, guaranteeing sample integrity, high quality data and uninterrupted workflow. They are useful in PCR, and HTS sample storage and are available in multiple sizes. For a perfect, leakproof seal with most popular plates.
Alkali Scientific CellPro™ 24-Well, Silicone Sealing Mats, 50/pk, DNase, RNase & Pyrogen-Free
CellPro™ 24 Well, Silicone Sealing Mats seals 24 wells at a time for minimal evaporation / sample loss, guaranteeing sample integrity, high quality data and uninterrupted workflow. They are useful in PCR, and HTS sample storage and are available in multiple sizes. For a perfect, leakproof seal with most popular plates.