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Custom Silicone Stoppers & Plugs

Silicone stoppers and plugs that seal, mask and blank holes and ports — tapered, straight, threaded and vented, molded to your opening and tolerance.

Sealing & Masking

Stoppers & Plugs That Fit and Seal

A stopper or plug closes off an opening — to seal a fluid, mask a hole during finishing, or blank an unused port. We mold silicone stoppers and plugs in tapered, straight, threaded and vented styles that fit securely and stay put.

  • Tapered & straight plugs — flexible fit across hole sizes
  • Threaded & vented stoppers — for pressure relief
  • Masking plugs — for paint, powder and plating lines
  • Food & medical grades — FDA / LFGB compliant
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Finished silicone stoppers and plugs stacked in trays with inspection labels at the CYES SILICONE factory
Material & Performance

Choosing the Right Stopper or Plug Material

Match the compound to your sealing, masking or blanking environment.

RequirementRecommended gradeTypical hardness
Food & beverage contactFood-grade silicone (FDA / LFGB)50 – 60A
Medical / pharmaceuticalMedical-grade platinum-cured silicone40 – 50A
Paint / powder maskingSolid silicone rubber (RoHS / REACH)60 – 70A
Fuel & solvent exposureFluorosilicone (FVMQ)60 – 75A

Compression Set

Low-compression-set compounds keep the plug sealed and reusable over repeated cycles.

Temperature Range

Rated from -40 °C to +230 °C depending on the compound selected.

Precision Fit

Mold cavities machined to ±0.01 mm, with finished-part tolerance confirmed during DFM.

Common Questions

Silicone Stopper & Plug FAQ

The terms overlap. A stopper typically seals a container opening (such as a bottle or vial), while a plug blocks a hole or port (such as a paint-masking plug). We mold both styles in tapered, straight, threaded and vented forms.
Yes. Tapered silicone plugs flex to seal a range of hole diameters with a single part, which reduces part numbers and simplifies masking lines. We size the taper to your hole range.
Yes. We mold silicone masking plugs that withstand curing temperatures and resist paint adhesion, so they pull cleanly and can be reused across multiple cycles.
Yes. We offer food-contact and medical-grade platinum-cured silicone stoppers tested for FDA 21 CFR, LFGB, RoHS and REACH compliance as required.

Need Silicone Stoppers & Plugs?

Send your drawing, sample or dimensions. We will review material, hardness and tolerance before quoting.

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