Custom Gasket Strips

When standard gasket tape isn’t an exact fit, Stockwell Elastomerics offers custom gasket strips from a wide range of stock materials. Stockwell Elastomerics maintains a full inventory of high performance gasketing materials including soft silicone (solids), silicone foams, silicone sponges, neoprene sponge, and PORON microcellular urethane foam. These materials can be laminated with 3M pressure sensitive adhesives and cut into custom strip gaskets, typically without any tooling charge.

Performance Properties of Gasket Strips

Typical applications for custom gasket strips that require specific performance properties include:

• Submerged Water Sealing – submerged applications generally require single piece gaskets vs. strip gaskets. These are usually best served with solid gasket materials; often low durometer silicone (soft silicone) performs well.
• Hose Down Water Sealing – single piece gaskets work best however interlocked or bonded gasket strips may be sufficient depending on enclosure design and water pressure. Closed cell sponge, closed cell foam and solid gasket materials (soft silicone) perform well.
• Dust and Light Splashing – gasket strips often work well; open cell foam, closed cell sponge, and closed cell foam are commonly specified.
• Compression Set Resistance – this is a key performance discriminator between PORON® cellular urethane, silicone foam and closed cell silicone sponges versus low cost blended neoprene and PVC foams. For indoor applications such as on industrial controls, PORON provides a good value for long term performance. For outdoor enclosures that see the full range of environments, silicone foam or closed cell silicone sponge will perform better over time.

Adhesive Backings for Strip Gaskets

Stockwell Elastomerics offers over 20 pressure sensitive adhesives. Most of the adhesives supplied on gasketing tape materials fall into 3 categories:

• Film Supported Acrylic (also known as double coated PSA) – PSAs are constructed from coating each side of a thin PET film with adhesive. When a supported PSA is laminated to a “stretchy” rubber material, the thin PET film gives the strip gasket (or gasket tape) dimensional stability. This is useful to prevent an assembly technician from stretching the strip gasket during installation. The recommended adhesive for general purpose applications is Adchem 256M acrylic adhesive.
• Unsupported Transfer Film – these are .002″ to .010″ films of adhesive on self-wound rolls of release liner. Transfer film adhesives can be stretched and conform to uneven surfaces or bends (to reduce the number of butted splices) during installation. The recommended transfer adhesive backing for strip gaskets is 3M 9485 acrylic (0.005″ thick). Unsupported transfer film adhesive is good for cast metal enclosures and sheet metal enclosures with uneven surfaces. The recommendation for this application is 3M 350 series (9485, 9675) acrylic transfer film adhesive.
• Low Surface Energy Adhesives – LSE adhesives have been developed to adhere to “tough to stick to” materials such as power coated metal surfaces and some plastics. LSE adhesives are available in film supported constructions such as 3M 9490LE and transfer film adhesives such as 3M 9675, 3M 9485 and 3M 9472LE.

Manufacturing Gasket Tape vs. Strip Gaskets

Gasket tape is made by slitting a master roll of material to a prescribed width. The length may be specified, though there are limitations based on the thickness of the material and master roll put-up. In contrast, strip gaskets can be made from any variety of roll stock material such as silicone foam, urethane foam, silicone sponge, or neoprene sponge. These materials are typically provided with an adhesive, peel and stick backing for ease of installation.

Applications for Strip Gaskets

The most common uses are dust and water protection for large enclosures and electrical housing gaskets. Strip gaskets can be used for ingress protection standards IP61, IP62 and IP63. Aggressive wash down requirements such as IP64, IP65 and IP66 may require bonded corners to prevent the ingress of pressurized water. The same holds true for NEMA 4 and UL 50 enclosures.

Cost Benefit of Strip Gaskets

The key benefit to using a strip gasket is the reduced material cost. Stockwell Elastomerics manufactures custom gasket strips based on customers’ needs. To have a strip gasket manufactured by Stockwell Elastomerics, the required information is:

• Strip width
• Material thickness
• Type of pressure sensitive adhesive (PSA) backing

Need Help with Gasket Strips?

Stockwell Elastomerics can help customers select the proper material and adhesive backing for each strip gasket application. Note: with the slitting process there typically is a minimum order requirement.

Free Whitepaper: Gasket Tape – Silicone Sponge and Silicone Foam for Long Term Sealing Performance (PDF for immediate dowload)

This gasket tape whitepaper discusses silicone product options that will last and perform for the entire anticipated life of the electrical equipment including those installed in outdoor conditions in the harshest environments.