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
Ace Glass, Inc. 250mL gas wash stopper only, porosity A
250mL gas washing stopper with porosity A (145-174 micron) 25mm fritted disc diameter, and 40/35 joint. Inlet/outlet arms are 8mm O.D.
Ace Glass, Inc. 19 STOPPER FLSK LGTH 19 Stopper Flsk Lgth
Size 19 hollow flask length standard taper stopper
Ace Glass, Inc. #80 solid PTFE plug, 7855-766 FETFE O-ring back seal
#80 solid PTFE plug, 7855-766 FETFE O-ring back seal
Ace Glass, Inc. 24/40 gas washing bottle stopper without 125mL bottle
24/40 stopper for 125mL gas washing bottle. Bottle not included.
Ace Glass, Inc. #9 PTFE Stopper with Polypropylene Extraction
#9 standard taper PTFE stopper with polypropylene extraction nut for easy removal from outer joints.
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.