Technical Tips
The following technical tips are provided with links to the Elastomerics Blog where these tips were originally posted.
RMA Tolerance, Fixed and Closure Tolerances Explained
A common technical question is about the Rubber Manufacturers Association (RMA) tolerance table and what "Fixed" and "Closure" dimensions are. A way to think of this is a clam-shell mold (top and bottom halves). Stockwell Elastomerics does liquid injection molding (LIM) with liquid silicone rubber (LSR) and does rubber compression molding with specialty silicone rubber materialsRead more on RMA fixed dimensions and RMA closure dimensions ...
Rubber Compression Set, Stress Relaxation and Creep
What are compression set, stress relaxation and creep in relation to elastomeric gasketing? All these items are related but different measurements of stress/strain and deformation and all are affected by temperature. Check out a brief overview of compression set, stress relaxation and creep, and how they relate to commercially available gasketing materials.Read more about compression set, stress relaxation and creep ...
Light Leak Gasket
While indoor LED lighting and LCD displays are on opposite sides of the spectrum, they often share a common problem, light leaking. Light leaking may not be an official terminology, but it adequately describes the problem of light emitting from an enclosure or housing where it is not intended. Ambient lighting fixtures, such as fluorescent, LED, or incandescent have areas or joints where the designer wants to contain the light – or prevent a light leak.. This can be addressed with lightweight foam materials to create a light leak gasket.Read more about light leak gaskets ...
Touch Panel Assembly Gasket Design
Like most gasket designs, performance can be linked to the type of material and how it relates to a specific application - this holds true for touch panel gaskets. There are environmental considerations, gasket geometry, manufacturability and industry specifications. A video highlights a Poron gasket with a double coated, repositionable adhesive which gives the soft gasket X and Y axis dimensional stability to help with installation.View the video and read more about touchscreen gaskets ...
Repositionable Adhesive Backed Gasket
Stockwell Elastomerics offers many pressure sensitive adhesive backing options for gaskets. Standard adhesive such as 3M 467, Adchem 256M and 3M 9485 work very well for bonding to metals, plastic and glass, however some applications require the ability to remove or reposition the gasket during installation. Other applications may need non-destructive reworking after being in the field for some period of time. These type of applications may benefit from a repositionable adhesive.View the video and read more about adhesive backed repositionable gaskets ...
Poron Foam Battery Compartment Pad / Battery Cushion
A common element of ruggedizing portable electronic devices is holding the battery in place as well as protecting it from a mechanical shock event, such as a drop to concrete. Often, there are small gaps left between the battery and the compartment cover, this gap allows movement and impact that can damaged the battery or disconnect power. Designers of ruggedized devices commonly use Poron cushioning pads to fill the gap between the battery and cover.Read more about battery compartment pads and cushions ...
Electrically Conductive Rubber – EMI Gasket Materials
Electrically conductive gasket and gasket materials are typically specified for EMI applications. Commercial EMI applications often call for nickel graphite filled silicone due to cost, whereas military and aerospace applications often call for silver coated aluminum to meet Mil-G-83528C specifications. Military or aerospace may also use fluorosilicone vs. silicone for its fuel and chemical resistance.View the video and read more about electrically conductive rubber and EMI gasket materials ...
UL Listed Gasket Materials, UL Rated Gaskets, UL Gasket
The obvious part of gasket design is picking a material that meets functional requirements such as water or dust sealing. However a significant component of the design process that less obvious includes selecting materials that meet specifications, such as MIL, IP, NEMA or UL. Underwriters Laboratories is the leader in safety testing, the two most common requirements which relate to gaskets are UL 94 (UL94) and UL 50 (UL50). Stockwell Elastomerics maintains an extensive on-site inventory of a wide range of materials that are UL listed for one or many UL requirements including: UL 94, UL 50, UL 50E, UL 508, UL 157, UL 1570, UL 1571, UL 1572.Read more about UL listed gasket materials and UL rated gaskets ...
Strip Gasket, Gasket Tape, Strip-N-Stick® – Sponge and Foam Gasketing Tapes
Gasket Tape also called; Strip Gaskets, Slit to Width Gaskets, Foam Tapes or Strip-N-Stick® (Registered Trade Mark of Saint Gobain) are all names for sponges or foams that have a peel and stick adhesive backing which are then cut to a prescribed width. Stockwell has extensive experience in gasketing and sealing applications and has hand picked the best performing materials for strip door gaskets, enclosure gaskets, NEMA gaskets and IP gaskets.Read more about strip gaskets, gasket tape, and sponge/foam gasketing tapes ...
LCD Display Gaskets, Touch Screen Gaskets
Touch screen displays have been in use for many years but are more prevalent now in many handheld devices. Each touch screen application, while similar in function, requires different gasket protection due to their varying designs for in-use environments. Indoor consumer touch screens more often just require dust gaskets with some mechanical shock protection. Outdoor LCD touch screen displays require a higher level of gasket protection, as do industrial control displays.Read more about LCD display and touch screen gaskets ...
UV Resistant Gasket and Ozone Resistant Gasket
Gasket performance hinges on the integrity of the gasket material over its life expectancy. Two significant elements that can be detrimental to gasket life and integrity are ultraviolet (UV) light and ozone. Silicone rubber is a top performer in battling degradation, with excellent UV and ozone resistance. Since silicone rubber is inorganic it does not have the carbon backbone in its polymer structure that makes the organic polymers prone to being attacked by UV and ozone.Read more about UV and ozone resistant gaskets ...
Gasket Design Guide, Machine Design Article
There are many variables in designing a gasket. The Gasket Design Guide article in Machine Design (November, 2010 issue) written by Stockwell Elastomerics' Application Engineer Steve Hughes speaks to some of the key elements of gasket design. The article touches on functional considerations, material selection, mechanical factors and manufacturability.Read more about the Gasket Design Guide article ...
LED Gaskets for Commercial & Municipal Lighting
Light Emitting Diode (LEDs) technology has been around for a long time, but with more recent advances (i.e. high power LEDs), new lighting products are serving commercial and municipal markets. Low energy consumption and long service life are primary benefits for LED city lighting and area lighting for parking lots and walk-ways.Read more about gaskets for LED lighting and similar applications ...
Silicone Rubber Gaskets
Silicone rubber is more often being specified for gasket material, especially environmental seals. Silicone is made in wide variety forms such as solid silicone sheets, closed cell silicone sponge sheets and open cell silicone foam. All of these are available in a range of durometers and firmnesses.Read more about silicone rubber gaskets and their technical properties ...
New DP-1001 Silicone Pressure Sensitive Adhesive product now available
Stockwell Elastomerics launched a new product - Stockwell DP-1001. This silicone pressure sensitive adhesive (PSA) with easy to remove release liner can be used with die cut silicone gaskets and cushioning pads, greatly reducing the time required to remove the release liner. It also performs well in high temperature applications. As part of this new product launch, Stockwell Elastomerics is new offering a DP-1001 product sample pack so that customers can see and touch the product to experience firsthand its benefits.Read more about Stockwell DP-1001 ...
View the Stockwell DP-1001 product demo video ...
Transportation Cushioning Pad for Wind Turbine Blade
Stockwell Elastomerics has been working with a major Wind Turbine Blade manufacturer on a design and logistics challenge - how to hold and transport fragile wind turbine blades that are 110 feet long and greater - without squeezing the blade too firmly.Read more about this transportation cushioning pad special application ...
UL94 V0 Flame Retardant Silicone Sponge Rubber
St. Gobain’s R-10400-M flame retardant silicone sponge is a unique expanded silicone sheet product. It has similar mechanical properties as standard silicone sponge rubber but with flame resistance, R-10400 holds an aggressive UL94 V0 flame rating.Read more about R-10400-M flame retardant silicone sponge ...
View R-10400-M burn test video ...
Conductive Pad, ESD Pad, Conductive Adhesive – Cryogenic Exposure
SE65 is a carbon filled electrically conductive silicone rubber, durometer of 65 Shore A scale, typically used to dissipate or ground out static while providing some compliance and cushion. SE65 can be bonded to a conductive surface (aluminum or steel) using Stockwell’s RTV-60-CON which is also a carbon filled silicone based RTV (Room Temperature Vulcanizing), making a very intimate and strong bond when the surfaces are prepared properly.Read more about conductive pads, ESD pads, and conductive adhesives under cryogenic exposure, view video ...
Gasket Tape, Strip Gasket and Strip-N-Stick Gaskets
Gasket Tape, Strip Gasket and Strip-N-Stick™ are common names for a strip of gasket material with peel and stick adhesive backing. Strip gaskets are good for dust and light pressure water seals such as NEMA3, IP61, IP62.Read more about gasket tape and strip gaskets ...
Formex – Thin UL Rated Polypropylene Sheet
Formex GK polypropylene sheet has been engineered to meet electronic equipment requirements. Over the last few years Stockwell has been laminating Formex to other UL94 rated materials such as HT-800 and BF-1000 silicone foams.Read more about Formex thin UL rated polypropylene sheet ...
Steel Rule Die for Custom Gasket Cutting
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.Read more about steel ruled die for custom gasket cutting ...
Rubber Temperature Range
Whether you are designing a pad or gasket it is important to know how the environment will affect your part. Excessive heat can be linked to many gasket failures in the form of compression set.Read more about the general operating temperatures for commonly used materials...
Silicone Foam - Waterjet Cut & Foam Assembly
Stockwell has a dedicated production cell for assembly where silicone foam, silicone sponge, urethane foam and EMI materials are bonded, lamininated and/or assembled.Read more about silicone foam waterjet cutting and foam assembly...
Platinum Cured Silicone vs. Peroxide Cured Silicone
Addition or platinum cured silicone rubber offers an increasingly popular alternative to conventional peroxide cure silicone products – especially for healthcare applications which require the utmost purity and cleanliness of materials.Read more about Platinum Cured Silicone compared to Peroxide Cured Silicone...
Fast Turn Gaskets
Stockwell often receives urgent calls 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 and has many production capabilities to allow for quick responses to urgent requests.Read more about helpful hints for fast gaskets to fix a problem or meet a deadline...
Jointed Silicone Gasket
Stockwell joins silicone sheet regularly for large gaskets that exceed standard silicone sheet manufacturing widths.Read more about jointed silicone gaskets...
Large Gasket Splicing and UV Corner Bonded Gaskets
Stockwell offers UV corner bonding for large gaskets. This process includes die cutting or water jet cutting the gasket “legs” with a dovetail type joint at the ends. The jointed ends are then bonded with a UV sensitive adhesive.Read more about large gasket splicing...
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 rubberRead 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 ...
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