Custom molded silicone rubber gasket/square rubber seal/gasket

A square rubber seal should sit flat around its intended opening before the mating face is applied. The silicone gasket's locating features, corner radii, and side dimensions need to align without stretching. A part held correctly at one corner can still bow along another side if the overall outline does not match the receiving surface.

Define the thickness and supported sealing width around the complete perimeter. Include fastener holes and any passages that must remain clear.

Bring the faces together evenly and inspect for trapped corners or an inner edge pushed into the opening. During maintenance, look for uneven flattening near fasteners compared with the middle of the sides. Correct a closing or support issue where needed before fitting another gasket. Adding thickness across the whole square should not be used to hide a local gap, since it changes the contact at regions that may already be correctly compressed. Retain adequate material beside each corner fastener.

Material options

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

Hardness selection

Silicone: 20–80 Shore A. Adding thickness across the whole square should not be used to hide a local gap, since it changes the contact at regions that may already be correctly compressed.

Custom dimensions

The silicone gasket's locating features, corner radii, and side dimensions need to align without stretching.

Fit & assembly

Correct a closing or support issue where needed before fitting another gasket.

Use & inspection

Bring the faces together evenly and inspect for trapped corners or an inner edge pushed into the opening.

Photos illustrate structure or material only. A square rubber seal should sit flat around its intended opening before the mating face is applied. ETOL directly manufactures custom-shaped silicone and rubber parts to your requirements.