Conical Silicone Plugs – Rubber Stopper End Caps for Pipe & Tube Sealing | 1–16mm

Each size is listed as A x B x C, where A is the small-end (tip) diameter, B is the large-end (base) diameter, and C is the height. Measure the inner diameter of your pipe or hole opening. Choose a plug whose A dimension is slightly smaller and whose B dimension is slightly larger than the opening — the taper creates a secure interference fit as you push it in.

Example: a 1/4 in (approx 6.35mm) pipe bore would typically suit the 6 x 10 x 19mm plug. A 3/8 in (approx 9.5mm) bore would generally fit the 9.5 x 14.5 x 20mm plug. When in doubt, size up — a slightly larger plug compresses more and seals more firmly.

Silicone rubber generally withstands temperatures from approximately -60°C (-76°F) to 200°C (392°F). These plugs are typically suitable for powder coating ovens (which generally run at 160–200°C / 320–392°F) and anodizing baths. For sustained exposure near the upper limit, confirm suitability with your specific process conditions before committing to a large production run.

Silicone is inherently UV-resistant and does not corrode, making these plugs generally suitable for outdoor use, mild chemical exposure, and humid or wet environments. They are not recommended for prolonged immersion in strong solvents (e.g., acetone, MEK) or concentrated acids without prior testing.

These are smooth tapered plugs — they do not engage threads. They seal by compression fit into the bore of a pipe, tube, or hole. They are compatible with both metric and imperial pipe bores across the 1–16mm small-end diameter range. For threaded hole masking (e.g., powder coating), the plug tip sits inside the thread bore and the taper seals against the chamfer or bore wall. Always verify the bore diameter against the plug's A dimension before ordering.

Yes. Silicone is elastic and durable, so these plugs can typically be removed and reinserted multiple times without losing their sealing ability, provided they are not exposed to temperatures or chemicals beyond their rated limits. In production environments, inspect plugs periodically for tears or permanent deformation.

For powder coating hole masking, select a plug whose small-end (A) diameter is slightly smaller than the hole you need to mask. Common choices for threaded holes:

• M3–M4 holes → typically 1.5 x 4.5 x 16mm
• M5–M6 holes → typically 3.5 x 9 x 30mm or 4.5 x 8.5 x 16mm
• M8 holes → typically 6 x 10 x 19mm
• M10 holes → typically 8.5 x 11 x 23mm or 9.5 x 14.5 x 20mm
• M12–M14 holes → typically 11 x 16 x 20mm or 14 x 19 x 20mm
• M16 holes → typically 16 x 25 x 25mm

These are general guidelines — always measure your actual bore before ordering.

Both colors are made from the same silicone compound and offer identical performance. The color choice is primarily for visual identification — black plugs are easier to spot against light-colored workpieces, while white plugs stand out on dark surfaces. In high-volume production, using different colors for different size ranges can also help prevent mix-ups.