Custom NBR rubber sealing O-ring/silicone washer for machine

An NBR rubber sealing O-ring is selected for a groove based joint, while a silicone washer uses a different contact geometry. In a machine that contains both formats, replacement parts should remain clearly identified so a similar outside diameter does not lead to an incorrect substitution. Material and shape each have a separate role in the final fit.

For the ring, compare the section and installed diameter with the groove and closing gap. For the washer, check its face dimensions, thickness, and supporting surfaces. Select the specified compound around the contacting medium and temperature instead of treating NBR and silicone as interchangeable options.

Keep each part clean during assembly and protect it from sharp threads or edges. A ring should sit without twist, while a washer should remain centered as the joint closes. After disassembly, inspect the damaged area alongside its mating feature. Cuts, extrusion, or uneven flattening can reveal a fitting or support problem that a new seal alone will not correct. Preserve the intended joint geometry when choosing the replacement.

Material options

NBR / Silicone. Custom formulation and color for the intended contact conditions.

Hardness selection

Rubber: 30–90 Shore A. Silicone: 20–80 Shore A. For the ring, compare the section and installed diameter with the groove and closing gap.

Custom dimensions

For the washer, check its face dimensions, thickness, and supporting surfaces.

Fit & assembly

Cuts, extrusion, or uneven flattening can reveal a fitting or support problem that a new seal alone will not correct.

Use & inspection

After disassembly, inspect the damaged area alongside its mating feature.

Photos illustrate structure or material only. An NBR rubber sealing O-ring is selected for a groove based joint, while a silicone washer uses a different contact geometry. ETOL directly manufactures custom-shaped silicone and rubber parts to your requirements.