Gasket Tape, Strip Gasket & Strip-N-Stick

Gasket Tape, Strip Gasket and Strip-N-Stick™ are common names for a strip of gasket material with peel and stick adhesive backing. Gasket tape is supplied on a roll and widths can be cut as needed, typically 0.5” to 3”. Strip gasket is good for dust and light pressure water seals such as NEMA3, IP61, IP62. It should be noted that closed cell foam, closed cell sponge or solid materials should be used in water sealing applications and the enclosure should not allow water pool on the gasket. For aggressive water seals such as NEMA 4, NEMA 4X, IP65 & IP66, enclosure design, material selection, and gasket joints play a greater roll in enclosure sealing.

Gasket tape materials can vary from open cell urethane foams such as Poron, closed cell silicone sponge such as R-10470 & R-10480 and even solid rubber materials can be provided in Strip Gasket form. Various adhesive backings are also readily available, most common are acrylics but rubber and silicone adhesives are also available. Gasket tape is available in standard configurations such as the Saint Gobain’s Strip-N-Stick™ silicone sponge and silicone foam tape products. Stockwell can also apply any variety of 3M or Adchem adhesive to Poron foam, Neoprene sponge, Bisco silicone foams and slit strips (Gasket tape) as needed.

For more information on Gasket tape and strip gaskets, visit http://www.stockwell.com/, call 215-335-3005 or email service@stockwell.com.

Steel Rule Die for Custom Gasket Cutting

Often when people hear “custom” and think high cost; special setup charges, and tooling charges. In reality custom gaskets can be custom made for relatively low cost. If volumes warrant die cutting (often 500+ pcs) a steel rule tool can be made. A die for a six inch square window gasket with fastener holes at each corner can be made for less than $200. When amortized over a few thousand pieces, tooling cost quickly become pennies/per part.

Steel ruled dies are often made by accurately laser burning the part geometry into engineered, dimensionally stable plywood. Then a long steel blade (almost like a razor blade) is precisely bent and press fitted into the wood. Holes are made by pressing punch sets into the plywood. Tools in the 12” x 12” range can hold a tolerance of less that .012”.

Stockwell uses steel rule dies to cut Poron urethane foam, silicone foam, silicone sponge, and neoprene sponge. It is important to know that softer and thicker foam or sponges tend to have wider tolerances because the material compresses before it is cut through. Solid silicone gaskets, thermal gasket, emi gaskets can also be cut with steel rule dies.

Gaskets and pads can be made many ways. Stockwell takes into consideration gasket material type, gasket thickness and quantity to determine the production method that is most cost effective. Very tight tolerance gaskets or low volume gaskets can be waterjet cut with no tooling charge.

For more information about gaskets or gasket materials cut with steel rule dies, visit http://www.stockwell.com/ or call 215-335-3005.

Rubber Temperature Range

Whether you are designing a pad or gasket it is important to know how the environment will affect your part. In most cases, pad and gasket are dynamic in their operation. As an example a door gasket on a NEMA enclosure will compress and rebound as the enclosure heats up and cools off due to thermal expansion. If the gasket loses its ability to rebound (i.e. takes a compression set) or even worse brakes down, the seal could be lost leading damage or system failure.

Excessive heat can be linked to many gasket failures in the form of compression set. I recently saw a sprinkler control enclosure that used a sponge cord (likely a chloroprene blend) that took a major compression set. This set made the gasket virtually useless. In a wind driven rain situation, there would be ingress of water. Luckily this box was mounted inside a garage. It is important to know that elevated temperatures can encourage compression set. ASTM has tests for sponges and foams at 2 different temperatures 158°F & 212°F.

Catastrophic failure of a gasket or pad can also be attributed to exceeding the operational temperature of the “rubber”. Below is a list of materials and their general operating temperature ranges. Note, refer to specific manufactures datasheet before selecting a material.

General Operating Temperatures for Common Materials*
Urethane: less than 250°F (121°C)

Natural Rubber: less than 250°F (121°C)

Chloroprene (Neoprene): less than 300°F (149°C)

Nitrile (Buna-N): less than 300°F (149°C)

EPDM: less than 400°F (204°C)

Fluorosilicone: 400 – 500°F (204 – 260°C)

Fluorocarbon: 400 – 500°F (204 – 260°C)

Silicone: 400 – 500°F (204 – 260°C)
*Temperatures are general, values will vary with grade. Refer to specific specifications for actual product temperature ratings.

For more information about gasket and pad materials such as solid silicone, silicone sponge, silicone foam, fluorosilicone sponge, Neoprene, EPDM, Nitrile, Poron urethane foams or other gasket materials, please contact Stockwell at (215) 335-3005 or visit our website at www.stockwell.com.

Silicone Foam - Waterjet Cut & Foam Assembly

One of the more interesting silicone foam parts Stockwell has made was a thermal insulating jacket for an electronic device. The material used was HT-800 silicone foam, the foam’s cellular structure gives the material insulating properties. HT800 is a UL94 V0 flame rated foam and also has electrically insulating properties.

The part shown below was constructed from standard “off the shelf” thicknesses of HT-800, though a few thicker layers required laminating. A variety of shapes were waterjet cut and hand assembled.

Stockwell has a dedicated Production Cell for Assembly where silicone foam, silicone sponge, urethane foam and EMI materials are bonded, lamininated and/or assembled. For more information on Stockwell Elastomerics assembly capabilities other silicone rubber, closed cell sponge, & Poron applications, please contact Stockwell at (215) 335-3005 or visit our website at stockwell.com.

Fluorosilicone – Fluorosilicone Sponge, Solid Fluorosilicone, Electrically Conductive Fluorosilicone

Fluorosilicone (FVMQ) is fluorinated version of silicone which gives this polymer superior chemical resistance. Fluorosilicone is used where extreme temperature ranges (relative to “rubber”) are required and where aggressive fluids may be present.

The Aerospace, Automotive and Green Energy industries often use fluorosilicone for its cross-functionality. Fluorosilicone has ability to maintain its mechanical properties over a wide temperature range, is UV and ozone resistant and has excellent chemical resistance particularly to fuels and oils.

Stockwell offers fluorosilicone in its many forms including solid fluorosilicone sheets, soft fluorosilicone sponge, molded fluorosilicone parts, and electrically conductive fluorosilicone (used for EMI gaskets). Sheet grades are readily die cut or waterjet cut on site. Similarly, fluorosilicone parts are molded onsite at Stockwell Elastomerics.

For more information about solid fluorosilicone gaskets, fluorosilicone sponge, or other gasket fabrication applications, please contact Stockwell at (215) 335-3005 or browse our website.

Link to: fluorosilicone datasheets

Fast Gasket, Quick-Turn Gasket, Next Day Gasket, or Quick Gaskets!

It is not a rare occurrence at Stockwell to receive an urgent call requesting next day gaskets or pads. Many times there is field requirement or engineering build where time is critical. Stockwell inventories a wide range of materials and thicknesses. Stock materials include solid silicone, closed cell silicone sponges, UL rated silicone foams, Neoprene sponges, EMI gasket materials, and Thermal management materials just to name few. These stock materials in combination with 3 in-house water jet cutting, die cutting and molding presses with 12” x 12” sheets molds, allow for quick response to urgent request.

Helpful hints for fast gaskets to fix a problem or meet a deadline:
- Supply an electronic CAD file (2D .dxf or 3D .iges)
- Work with in-stock materials
- If an adhesive backing is required, inform us of the type of metal, plastic or painted surface to be bonded to
- Indicate smallest quantity required
- Provide ship-to information and carrier account number- Supply a credit card or purchase order (existing customers)

Providing an electronic CAD file helps expedite the Water Jet programming. With a wide cross section of materials in stock, Stockwell can usually find a material to meet gasketing requirements. Since it is often a race against the clock / shipping pickup, knowing the minimum quantity helps to manage processing. Often additional parts can ship within a few days.

BF-2000 Ultra Soft Silicone Foam

Previously called EP-2022, BF-2000 Ultra Soft Silicone Foam (liquid silicone base) has been a nice addition to Stockwell’s line of silicone products. With a typical force deflection of 1.5psi required to deflect the material 25%, it is the softest silicone foam product currently offered by Stockwell. BF2000 has excellent rebound (compression set resistance), a wide operating temperature range, is UV resistant and is UL94 V0 flame rated. These properties lend themselves to cushioning and padding for electronics or dust gaskets. LCD gaskets or touch screen gasket are common applications due to the very low rebound force. Like the vast majority of materials carried by Stockwell, pressure sensitive adhesives (PSA, both acrylic and silicone adhesives) can be applied to one or both sides of the foam.

Also in our Liquid Silicone Foam product line are:

BF-1000 is an Extra Soft Silicone Foam with an open cell structure

HT-870 is a Soft Silicone Foam with an open cell structure

HT-800 is a Medium Silicone Foam with a modified closed cell structure

HT-820 is a Firm Silicone Foam with a modified closed cell structure

HT-840 is an Extra Firm Silicone Foam with a modified closed cell structure

F-12 is similar to BF-1000 except with a fabric finish on one side and slightly courser cell structure

All the above silicon foam products listed are UL94 V0 listed (see specific datasheet for details). For more information on BF-2000 Ultra Soft Silicone Foam or other products offered by Stockwell Elastomerics please contact us at (215) 335-3005 or service@stockwell.com.

Large Custom Gaskets

Every so often we receive inquiries for large custom gasket. In some case they are extreme such as the one shown below. In many cases they are for NEMA enclosures (commonly NEMA 4). A single piece gasket generally offers the best seal, however many gaskets exceed the width of the material. In this case a jointed corner may be an option.

Single Piece - a single piece gasket will offer consistent deflection force around the gasket. The con to a large single piece gasket is the center waste. If engineer are making multiple gaskets they can create an assembly level drawing that show several gaskets nested.

Joint and Bond – when a single piece is required but the gasket dimensions exceed the material dimensions, a jointed and bonded gasket may be an option. In most cases this is a die or water jet cut male/female dove tail that is then UV bonded. This type of gasket needs to be evaluated to see that the extra labor of bonding does not exceed the material savings. Also, for foams and sponges the corners will be firmer than the gasket material.

Joint (no bonding) – similar to the Jointed and Bonded gasket, a male/female dove tail is die or water jet cut. In this case the gasket is provided in 4 pieces and is mated during installation. In some cases a bond is never required. This is most dependant on the enclosure configuration and the level of sealing required.

Materials most commonly used for large custom gaskets are silicone foam and silicone sponge. Since the sealing area is relatively large (i.e. square inches) the soft nature of these materials allow for lower closure forces to get proper deflection for sealing.

For more information please feel free to contact us at service@stockwell.com or 215-335-3005.