Glass stoppers

Premium Laboratory Glass Stoppers - Professional Grade Glassware

I've spent countless hours in the lab dealing with contaminated samples because of poor sealing, and let me tell you—investing in quality glass stoppers changed everything. Our borosilicate glass stoppers deliver the kind of reliability you need when sample integrity isn't negotiable.

Precision-Ground Glass Closure Systems for Laboratory Vessels

Borosilicate construction gives you unmatched chemical resistance across the pH spectrum, from concentrated acids to aggressive solvents. I've used these with everything from dichloromethane to hot caustic solutions without a single failure. The precision-ground joints create airtight seals that rival what you'd get with PTFE, but without the temperature limitations. When you're running reflux setups with a Dimroth condenser or Coiled-straight condenser,double layer, these stoppers maintain vacuum integrity for hours.

Standard Taper Joint Sizes and Specifications

• 14/20 joints: Small-scale synthesis and micro-volume work
• 19/22 joints: Standard analytical flasks and reagent bottles
• 24/29 joints: Workhorse size for most reaction vessels
• 34/45 joints: Large-volume preparations and industrial applications

Temperature range from -80°C to +500°C means you can go straight from liquid nitrogen baths to high-temperature distillations. Try doing that with rubber stoppers! The Type I borosilicate formulation has minimal alkali leaching—critical when you're doing trace metal analysis or working with pH-sensitive reactions.

Solid versus Hollow Stopper Applications

Solid stoppers excel at simple sealing tasks—think reagent storage, volumetric flask calibration, and sample preservation. I keep dozens on hand for titration work where you need quick access but reliable closure between measurements.
Hollow stoppers open up different possibilities. Insert Glass sticks for stirring applications, or use them with thermometer adapters and gas inlet tubes. They're fantastic when setting up vacuum distillations alongside your Pumps or Watering pumps—the hollow design lets you maintain connections while keeping the system sealed.

Chemical Inertness and Durability Factors

• Zero interaction with organic solvents, strong acids, and oxidizing agents
• Autoclavable at 121°C for sterile technique requirements
• Smooth surface finish prevents residue buildup and cross-contamination
• Dimensional stability—no swelling, shrinking, or warping over time

Clean them with chromic acid, piranha solution, or just soap and water—they'll look new every time. For chromatography prep work or pharmaceutical QC where contamination means starting over, glass stoppers aren't optional equipment, they're insurance.