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Technical Tips |
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Thick EMI Gaskets and EMI Gasket Options
Stockwell Elastomerics provides custom EMI gaskets regularly for a wide range of customers. Each application is a bit different; some can be cut from "off the shelf" sheets of nickel graphite filled silicone and others may require special fluorosilicone compounds or silver plated particle filled silicone for more conductivity.
Read more about EMI gaskets...
Gasket Compression Pecentage Calculation
An example of a gasket compression calcualtion using the Compression Force Deflection Curve for an HT-800 silicone pad.
Read more about EMI gaskets...
Acrylic Adhesive Backed Silicone Gaskets
Is Silicone PSA required for silicone material? We often see silicone based adhesive specified with silicone materials. Silicone adhesives are expensive as compared to acrylic adhesives, in some cases more than 5 times the cost of acrylics. Silicone PSA’s bond strength is not as good as acrylics and there are limited offerings. So why are silicone adhesives being specified?
Read more about acrylic adhesive backed silicone gaskets...
UMPC (Ultra Mobile Personal Computer), Ruggedizing Components
There is a new breed of personal computers on the market today, the Ultra Mobile PC or UMPC.
Stockwell has been ruggedizing electronics for many years. The key to achieving a truly rugged component is in the materials. For example, if a device is exposed to extreme low temperature and dropped it will rely on the cushioning pad for protection.
Read more about ruggedizing UMPC components...
High Performance Acrylic Adhesives on Silicone
Stockwell Elastomerics engineers have seen more requirements for silicone foam and closed cell silicone sponge enclosure gaskets and cushioning oads requiring high strength pressure sensitive acrylic adhesives for bonding to powder coated metal surfaces and certain low surface energy plastics. Secure lamination of acrylic pressure sensitive adhesives onto silicone rubber is not possible without priming the silicone rubber.
Read more about high performance acrylic adhesives on silicone ...
Rubber? - Rubber Gasket, Rubber Seals, Rubber Pads
It is interesting how the word "rubber", which historically has referred to natural rubber (also known as isoprene), has become a general term for elastomeric materials. Natural rubber is the original elastomer but there have been many more synthetic polymers developed, each with its own unique property.
Read more about rubber gaskets, rubber seals, rubber pads ...
Adhesive Backed Gaskets
For decades Stockwell has been applying pressure sensitive adhesive backings onto gasketing materials. Adhesive backed gaskets are very appealing to our customers for several reasons. More often engineers and designers are specifying adhesive backings for gaskets. A peel and stick gasket (or peel and stick vibration pad) offers some nice features that plain or non-adhesive backed gaskets don’t have.
Read more about adhesive backed gaskets ...
Large Custom Gaskets
What if you need a large custom gasket? In some cases they are extreme such as the one shown. 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.
Read more about large custom gaskets ...
Silicone Gaskets
Stockwell carries a wide range of silicone materials to meet the demands of most applications. Over the years silicone has grown to be our core product. We are seeing more and more engineers specifying silicone products into their design because of its unique properties. Today Stockwell stocks silicone sheet materials and compounds for custom molded silicone parts.
Read more about silicone gaskets and materials ...
Kiss Cut Gaskets and Pads
Kiss cutting is a die cutting process where a gasket or pad is supplied rolled up on the adhesive liner. If you were able to watch the cutting process in slow motion you would see the die penetrate the gasket or pad material, then continue through the thin adhesive layer and cut partially into the adhesive liner. The gasket or pad must have a pressure sensitive adhesive (PSA or "peel and stick") backing for kiss-cutting to be possible.
Read more about kiss cut gaskets and pads ...
Pressure Sensitive Adhesive-Supported Construction
Supported adhesives, also called double coated tapes, get their name from their construction. A thin plastic like layer (typically P.E.T.) is coated on both sides with a thin layers of adhesive. The most common family of Pressure Sensitive Adhesives are acrylic based. Adhesive manufacturers such as 3M, Adchem, and St. Gobain offer many varieties of adhesives with different bond strengths, temperature ranges, and mechanical properties.
Read more about supported PSA ...
Clear or Transparent Silicone Rubber
Although we usually think of silicone rubber as being pigmented red, black, or gray in color, silicone rubber is also available in clear, transparent sheets and as custom molded parts. Using our liquid injection molding (LIM) capability we can mold clear components in durometers from 10 to 70 Shore A. For flat gaskets we suggest HT-6240, a clear, high purity, 40 durometer silicone rubber
Read more about clear / transparent silicone rubber ...
Waterjet Cut Gaskets
Stockwell's 3 waterjet units are able to cut complex geometries with ease. A steel ruled tool or solid steel tool would be relatively expensive and still would not offer tolerances equal to the waterjet cut parts.
Read more about waterjet cut gaskets ...
Sponge EPDM Gaskets
EPDM (Ethylene, Propylene, Diene, Methylene) is commonly specified for outdoor gasketing applications. This is due to EPDM's excellent weather ability, and specifically its resistance to UV, ozone and oxidation. The closed cell structure minimizes water absorption which makes it a good material for enclosure gaskets needing occasional resistance to moisture and indirect water spray. EPDM sponges are available in various firmnesses from very soft to firm. EPDM gaskets are not recommended where they may come in contact petroleum based oils and certain chemicals.
Read more about sponge EPDM gaskets ...
Electrically Conductive Coated Pads for ESD Protection
Stockwell has a proprietary coating process that allows us to make custom electrically conductive silicone pads for ESD protection. The conductive pads are available in various thickness, firmnesses and geometries. The coated silicone sponge allows for a wide temperature range without loosing physical performance. The coating creates a conductive path on the surface of the material, parts can be partially or entirely coated to best suit the application.
Read more about electrically conductive coated pads ...
Thermally Conductive Fluorosilicone
Thermally conductive gap pads or gap filler pads provided for electronic thermal management have nearly always been fabricated from silicone rubber-based materials. We are continuing to evolve from a rubber fabricating company to a materials technology company. It’s all about the materials.
Read more about thermally conductive fluorosilicone ...
NEMA and IP Specifications Help Define Enclosure Gaskets
"Enclosure gasket" is a broad term that basically describes the gasket between a housing and a cover or door on the housing. The configuration and function of the enclosure can vary drastically, from metal to plastic, large to small, dustproof to waterproof , etc. NEMA and IEC International Protection (IP) standards help engineers define the specific requirements that need to be met for their design.
Read more about NEMA enclosure gaskets ...
Silicone Foam or Silicone Sponge?
Confused about the terms silicone foam versus silicone sponge. Closed cell silicone sponge is heat cured from a mixed silicone gum rubber base. Open Cell and Closed Cell Silicone Foam is cast from low viscosity liquid silicone which is catalyzed, rapidly mixed and cast onto a smooth plastic release liner.
Read more about silicone foam and silicone sponge ...
Silicone Gaskets and Silicone Gasketing Solutions
When is silicone the best choice? One of the key elements of silicone is its ability to maintain its mechanical properties over a wide range of temperature, -80° F - 400° F (60° C - 205° C) and in some case even colder or hotter. Silicone is also naturally UV resistant which makes it ideal for outdoor applications. There are silicone foams that are UL94-V0 rated which is commonly required in the transit and electronic sectors. It also performs well in compression set tests as compared to some of the organic elastomers, such as neoprene.
Read more about silicone gaskets ...
Material Jointing
Sometimes we are asked to make parts wider than available stock widths or lenghts. In some cases, in an effort to meet customers' needs, we will join materials. Most commonly jointed materials are silicones (solids, sponges or foams). Parts are generally section cut into "sub-pieces" then jointed, an alternate method is to join the materials then cut to size (if it will fit on the cutting bed).
Read more about material jointing ...
Material Laminations
Stockwell frequently does material laminations. In some cases we laminate standard sheet goods to create a non-standard thickness. In other cases we laminate materials for performance properties.
Read more about material laminations ...
New Silicone Pressure Sensitive Adhesive
Stockwell Elastomerics has a new film supported silicone pressure sensitive adhesive for silicone rubber gasketing. We teamed up with a specialty adhesive manufacturer to develop our new DP1001-2HT, which has 2 mils of silicone polymer adhesive on both sides of an amber colored polyimide film carrier.
Read more about silicone pressure sensitive adhesives ...
R10490-M fluorosilicone sponge meets AMS 3323
We have a number of gasket applications for R10490-M closed cell fluorosilicone sponge that are used in very harsh environments. These conditions include exposure to engine oil, hydraulic fluid, Coolanol, PAO and jet fuel over broad temperatures and outdoor conditions. The aircraft and aerospace industries have been the largest users of R10490-M to date.
Read more about R10490-M fluorosilicone sponge ...
It’s All Materials These Days
By any measure designing and drawing cushioning pads and gaskets is simple, but specifying the correct material is a whole different game. There are literally thousands of "soft good" material variations to choose from. Determining the best one for a customer’s applications is the real challenge. It's all about the materials!
Read more about materials and selection ...
RoHS Compliance
The European Union has adopted a directive called Restrictions on Hazardous Substances (RoHS). It eliminates or significantly reduces the use of certain substances from electronics products beginning July 1, 2006. Although Lead (Pb) seems to get most of the attention, other substances included in the directive are Cadmium (Cd), Mercury (Hg), Hexavalent Chromium (Cr VI), Polybrominated Biphenyl Ethers (PBBs) and Polybrominated BiPhenyl (PBDEs).
Read more about RoHS compliance ...
Radome Gasket
Check out this fast-turn project that involved a 17 foot long gasket. The requested material was .062" thick closed cell silicone sponge rubber with acrylic adhesive completely coating one side and a 1.0" wide strip of acrylic adhesive on the top side. As the 41" width exceeded the 36" typical material width, we realized splices would be needed.
Read more about large radome gasket prototyping ...
Contact Stockwell Elastomerics, Inc.
If you have additional questions or to request further clarification,
Contact Us for further assistance.
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