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
Chemglass Life Sciences Solid Rubber Stopper, #8-1/2, Black
These stoppers are suitable for practically all general laboratory uses. composition ensures resiliency and pliability over a long period and withstands laboratory conditions without hardening. The dimensions are in accordance with specifications established by the N. B. S. and are low in free sulfur (1/2%). Autoclavable at 250 degreesF for 30 minutes under water or steam conditions only (not dry heat). End user must test for their specific application.
Chemglass Life Sciences Stopper, Cap Style, 14/20, w/Hooks
Cap style stopper for use with inner joints.
Chemglass Life Sciences Rubber Stopper, #5, One Hole, Black
Rubber Stopper, #5, One Hole, Black. Similar to CG-3026 except with one hole. These stoppers are suitable for practically all general laboratory uses. Composition ensures resiliency and pliability over a long period and withstands laboratory conditions without hardening. The dimensions are in accordance with specifications established by the N.B.S. and are low in free sulfur (1/2%). Autoclavable at 250°F for 30 minutes under water or steam conditions only (not dry heat). End user must test for their specific application.
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.
Ace Glass, Inc. Septa, red rubber, sized for 24/40 joints, pk/144
Septa, red rubber, sized for 24/40 joints, pk/144
Ace Glass, Inc. 500mL gas wash stopper only, porosity B
500mL gas wash stopper with porosity B (70-100micron) fritted disc.
Cole-Parmer Solid Green Neoprene Stoppers, Standard Size 6.5; 15/Pk
Green neoprene stoppers withstand petroleum products, fats, oils, and organic chemicals. Stoppers exhibit good resiliency and shelf-life. Each stopper has its size in raised figures on top. Contain no sulfur.Autoclavable.
Chemglass Life Sciences Stopper, Drying Tower, 34/28
Cylindrical shaped drying tower has a 34/28 ground glass stopper. The stopper has a hole coinciding with a serrated hose connection sealed in the outer portion of the stopper neck and a second hose connection near the base of the cylinder. A hex base is sealed to the bottom of the tower for added stability.
Chemglass Life Sciences Stopper, PTFE, Minum-Ware
Stopper, PTFE, Minum-Ware. Solid PTFE stopper for use with all 14/10 microscale components.
Sigma Aldrich Fine Chemicals Biosciences Precision SealR rubber sep
Engineered for a push on fit in NMR tubes and ampules. The unique design provides a penetration point for cannulation and a dual seal inside the tube and on the outer sleeve. Will not break delicate thin-wall tubing. Manufactured from one certified raw material formulation for absolute consistency in all sizes from lot to lot.Storage Note for Natural Rubber Septa Store septa in a closed bag out of sunlight to retard blooming which is the formation of a whitish film on the surface of the rubber. Blooming is a natural process and does not affect performance. Remove visible bloom by washing or wiping off before use.
Sigma Aldrich Fine Chemicals Biosciences Precision SealR rubber sep
The recommended choice for use with organic chemicals and solvents pressure applications and cannulation techniquesPrecision Seal septa are designed specifically for the rigorous requirements of chemical applications.Precision fit Precision Seal septa have a longer tapered plug that seats firmly inside the glass joint or tube providing a sealing surface that is 50 to 80% greater than standard sleeve stoppers. The inner seal design of Precision Seal septa minimizes chemical and solvent vapor migration up the joint to the sleeve which can swell leak or fail from exposure. The surface texture of the rubber is similar to that of a ground glass joint and resists movement once seated.Non-contaminating Precision Seal natural rubber is lower in solvent extractables 1.9% vs. standard sleeve stoppers 5-6%. Precision Seal rubber is higher in density to minimize the effects of solvent degradation. They are manufactured from a single certified lot for absolute consistency.Safet