The Elastomerics Blog by Stockwell Elastomerics, Inc.

Friday, June 01, 2012

Light Leak Gasket


3M_9795B
3M 9795
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.  Most lighting fixtures require components, including foam, to be UL listed which may include UL 1570 (fluorescent), UL 1571 (incandescent), UL 1572 (HID) and UL 94 (flame rating).  Stockwell inventories HT-870, HT-800, HT-820 silicone foams which are UL listed for the above lighting fixture specifications.  These materials, as well as BF-1000, BF-2000 and F-12 low density silicone foams are UL94 listed and most meet UL 94 V0.  Additionally, silicone foams are UV and ozone resistant and withstand the effects of outdoor conditions and electrical enclosure environments for many years.
Handheld electronics also use gaskets to prevent light leaking from the display or illuminated buttons.  The typical material for display gaskets is Poron microcellular urethane foam.  Industrial grade Poron foams are available in a wide range of thicknesses and firmnesses that help designers make a good fit in tight electronic devices.
3M 9795B is a unique double coated adhesive that uses a black PET layer as opposed to the traditional transparent PET to help mitigate light piping thru the PET layer.  Stockwell offers 3M 9795B and 3M 467 (2 mil thick) as suggested adhesive options for light leak gaskets.


For more information on light leak gaskets, UL listed gaskets, silicone foam or Poron foam materials  offered by Stockwell, please visit www.stockwell.com or call 215-335-3005.

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posted by Steve Hughes at 3:04 PM 0 comments

Monday, May 14, 2012

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.


Stockwell offers two repositionable pressure sensitive adhesive options for gasket and cushions.  3M 9415 offers very low bond strength (5 oz/in) and Adchem 8311M offer medium/low bond strength (32 oz/in).  Both the 9415 and 8311M adhesives can be applied to Poron urethane foam, silicone foam or silicone sponge for repositionable dust gasket or water gaskets.  Common applications are LCD gaskets and touch panel display gaskets where thin walls often need realignment during assembly. Proper compression on these gasket, like all gasket applications, is required to make a proper seal.

For more information on repositionable gaskets, repositionable display gaskets, silicone foam or Poron foam gaskets offered by Stockwell, please visit www.stockwell.com or call 215-335-3005.

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posted by Steve Hughes at 1:31 PM 0 comments

Monday, February 20, 2012

Custom Gland Plate Gasket

Gland PlateGland plate gaskets are the "other" enclosure gaskets. Most often doors are the focus when it comes to sealing an enclosure. Stockwell Elastomerics often makes electrical enclosure gaskets, rack enclosures gaskets, and even handheld electronics battery door gaskets. Gland plates are another ingress point that also requires sealing.

A gland plate is a removable plate on an enclosure where wiring or connectors enter, it is often modified for custom applications. The gland plate is mounted to the enclosure with a series of fasteners. Proper sealing of the gland plate with an appropriate material for the application is critical for protecting the unit.

Gland Plate Gasket Poron urethane foam is a good option for NEMA Type 3, IP54 and lower. More aggressive requirements such and NEMA Type 4, IP64 and up may require closed cell materials or solid material. Outdoor applications intended for long life should consider silicone sponge, silicone foam or solid silicone due to its resistance against UV and ozone (possibly generated in the enclosure).

Gland plate gaskets or gland plate seals can vary widely depending on the enclosure design, the end use and environment. For more applications assistance or more information about a gland plate gasket or enclosure gasket, please contact Stockwell Elastomerics at 215-335-3005 or visit www.stockwell.com.

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posted by Steve Hughes at 1:49 PM 0 comments

Thursday, December 22, 2011

Gasket Tape, Touch Brochure

As announced in a recent press release, Stockwell Elastomerics is offering short lead times on high performance silicone gasket tapes. Silicone gasket tapes offer superior performance over most other polymers; the most common others are neoprene gasket tape. Silicone foam tape and silicone sponge tapes have excellent long term rebound, UV and ozone resistant, and a wide operating temperature. When many gasket materials firm up, silicone stays flexible and functional well below -40°F (-40°C). Stockwell offers HT-800, UL listed foam and R-10400, UL listed sponge in tape form (400FR), ready to be custom slit to width. Also available are Strip-N-Stick® (made by St. Gobain) medium firmness silicone sponge with either acrylic or silicone adhesive backing.

Click here to request a Gasket Tape Touch Brochure with product information and tactile sample buttons, or click on the image below.

Gasket Tape Touch Brochure from Stockwell Elastomerics

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posted by Steve Hughes at 5:30 PM 0 comments

Thursday, December 01, 2011

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. 

Poron Battery Pad maintains constant holding force
Poron® urethane foam is an excellent material for battery compartment pads since it is formulated to rebound (compression set resistant) consistently over a long period of time.  Materials such as polyethylene foam take a compression set readily, especially at higher than ambient temperatures.  Rogers Poron foam also has a UL94 flame rating (thickness dependent) which is often required for electronic devices.

Silicone foam products are the material of choice for extreme temperature applications, particularly sub-freezing temperature (e.g. 20°F  to -60°F), where Poron, Neoprene, EPDM and most other elastomeric foam materials will become rigid.  Silicone foam pads will remain compliant at these temperatures, capable of absorbing mechanical shock, where “frozen” materials will transfer energy thru the battery and housing. Open cell silicone foams like BF-2000, BF-1000, and HT-870 are very compliant and are UL94V0 (thickness dependent) rating that most foams.

Stockwell offers a wide variety of cushioning pad materials and a variety of adhesive backings.  For more information on battery compartment pads and battery cushion pads.  Please call 215-335-3005 or contact us.

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posted by Bill Stockwell at 5:12 PM 0 comments

Wednesday, November 02, 2011

Custom Silicone Parts Video, a Stockwell Elastomerics Overview

Stockwell Elastomerics is component manufacturer with a core competence in silicone rubber parts. The video below offers an overview highlighting a range of custom silicone parts; parts made by liquid silicone injection molding, custom silicone sponge tape, silicone foam tapes made from UL listed materials, waterjet solid silicone gaskets, custom die cut gaskets. Also highlighted in the video are adhesive laminations to Poron urethane foam and various silicone rubber materials.



While Stockwell is a silicone parts manufacturer, traditional closed cell sponge materials such as Neoprene and EPDM are laminated and converted regularly. For more information on Stockwell Elastomerics' silicone, Poron, adhesive and traditional rubber offerings, please contact Stockwell at 215-335-3005 or visit http://www.stockwell.com/.

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posted by Stockwell Webmaster at 11:53 AM 0 comments

Thursday, October 20, 2011

Custom Silicone Washer

Often Stockwell receives customer drawings that are simple, concentric, inside diameter (I.D.) outside diameter (O.D.) parts. These parts have varying ID and OD combinations, some having outside diameters of 3 feet or more, while others as small as 0.13”. Large ID OD parts are more often referred to as gaskets, smaller parts often are called washers or sometimes rubber seals.

Concentric ID OD gaskets, washers or rubber seals can be produced in a few ways; most common is by die cutting with steel punch sets which are available in many ID OD combinations but not all. Stockwell regularly water jet cuts customs washers and gaskets to meet non-standard ID OD combinations. Custom washers are often made from silicone, fluorosilicone, Neoprene, EPDM and fluorocarbon (also known as Viton® made by DuPont). Typically we think of washers being made from stock materials like solid silicone sheets for water seals or fluid sealing, however ID OD rubber seals are also used for dust sealing and even shaft cushions. Dust gaskets are often made from Rogers Poron®, which is a microcellular urethane foam.

Stockwell can manufacture custom silicone gaskets, custom foam gaskets, and custom rubber seals to meet most sealing and gasketing needs. For more information about custom washers and custom gaskets, please contact Stockwell at 215-335-3005 or visit www.stockwell.com.

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posted by Steve Hughes at 10:59 AM 0 comments