Silicone Carboy Stopper
Carboys are large, global glass bottles that are usually used to store and hold various corrosive liquids like acids, for example. They’re characterised by their unique shape – large, round body and a short, narrow neck. Back in the day, carboys were closer with corks, but as we all know, corks do not offer a perfect seal and seeing how carboys often store harmful and toxic liquids, we need something better than a regular cork. That is why we have manufactured a high-quality silicone carboy stopper.
A silicone carboy stopper is a rubber stopper used to create an airtight seal to prevent any gases or liquids from leaving or entering the carboy. Due to the widespread usage of carboys, silicone carboy stoppers can be found in many industries and in many environments. Another common use-case scenario for carboys is fermenting beers or other alcoholic beverages. As you know, CO2 is released during the fermentation process, alongside some other gases. With a silicone carboy stopper, a carboy is vacuum-sealed, but due to silicone’s nature and stopper’s design, it still allows for carbon dioxide to be released slowly instead of having it trapped inside the carboy, potentially causing it to burst. In addition to storing chemicals and fermenting alcoholic beverages, a silicone carboy stopper is also used to provide an airtight seal for carboys used to store and transport beer, wine, and even water.
Now, what makes silicone the perfect material for carboy stoppers are its natural properties like low thermal conductivity (does not get hot or cold) and excellent thermal stability (handles both high and low temperatures), low chemical reactivity, resistance to oxygen, ozone, UV lights, as well as high gas permeability (the CO2 releasing process we mentioned). In addition to all of that, silicone adheres to glass brilliantly, allowing it to create a perfect seal.
Stopper & Plug Size Catalog
Compare four stopper profiles and check the selected part dimensions against your opening and available depth. Each profile has its own drawing and dimension meanings.
Custom colors are available to your Pantone color code. Include the code in your inquiry.
RST T-Shaped Plugs
Match stem diameter A, flange diameter B, stem length C and flange thickness D. E refers to the underside recess; use the selected row and approved drawing to confirm the actual profile.

RSA Tapered Corks
Compare large-end diameter A, small-end diameter B and Height, in mm. The mating bore and required seating depth determine where the taper contacts the opening.

RSB Undercut Plugs
Compare neck diameter A, flange diameter B, flange-to-lip distance C and flange thickness D. Check panel thickness and rear clearance. E refers to the underside recess.

RSD T-Shaped Stoppers
Compare stem diameter A, flange diameter B, stem length C and head thickness D, in mm. Check the seating surface and available depth as well as the hole diameter.

Need a different fit? Share the opening dimensions, mating profile and intended use for a custom size.
Discuss Your RequirementsProduct specifications
- Product form
- Removable vessel-neck closure
- Material
- Silicone. Specify the compound grade for the selected service.
- Application focus
- Carboys, bottle necks, brewing equipment and wine bottles. Size the part against the selected assembly.
- Dimensions to confirm
- Opening diameter, closure profile, insertion depth and exposed grip. Match these to carboys and bottle necks.
- Profiles discussed
- Round profiles. Select the profile that matches the mating part and dimension that section explicitly.
- Contact conditions
- Acids, beer, wine, water and oxygen: define concentration, temperature and contact time, then check compatibility with the chosen compound.
- Exposure to evaluate
- Heat and cold cycling, sunlight or UV and ozone. Validate the selected material under the combined conditions.
- Seating check
- Check the sealing contact around the opening and the force needed for insertion and removal.
Need a quote or a custom part?
Send your requirements, drawings or samples to discuss standard and custom silicone rubber parts.
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