As announced in a recent press release, Stockwell is offering short lead times on high performance silicone gasket tapes. Silicone gasket tapes offer superior performance over most other polymers; most common 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.

To request a Touch Brochure with tactile sample buttons and more information, click the following link http://www.stockwell.com/pages/products_gasket_tape_touch.php or click on the image below.

Labels: custom gasket tape, custom silicone foam gasket, custom silicone gasket, custom silicone sponge gasket, rebound gasket tape, soft foam tape, UL 50, UL 508, UL 94

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.

Labels: battery compartment pad, battery cushioning pad, battery pad, custom pad, Pads, poron pad, UL 94

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/.

Labels: custom gasket tape, custom gaskets, custom silicone gasket, LIM, liquid silicone rubber molding, LSR, poron foam, silicone parts manufacturer, silicone parts video

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.

Labels: custom silicone foam gasket, custom silicone gasket, custom silicone rubber seal, custom silicone sponge gasket, custom silicone washer, poron dust gasket, poron washer

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.

Common Mil-G-83528C fill and polymer specifications:
Type A = Silver coated Copper – Silicone (65 Durometer)
Type B = Silver coated Aluminum – Silicone (65 Durometer)
Type C = Silver coated Copper – Fluorosilicone (75 Durometer)
Type D = Silver coated Aluminum – Fluorosilicone (70 Durometer)
Type M = Silver coated Glass – Silicone (65 Durometer)

Commercial applications more often specify nickel coated graphite for its cost savings. Most EMI applications can be satisfied with Ni/C products such as SNE-554, EC-2130, EC-2040 or SNEF-60.



The tan material in the video has silver coated aluminum particles, the dark grey material is nickel coated graphite. The video offers a simple visual of the rubber’s conductivity. The last example is showing a 3M conductive adhesive, the conductive path is from flows through the metal plate, up through the adhesive, through the conductive rubber into the LED.

Get more information on EMI gasket materials, or contact us via email: service@stockwell.com or phone: 215-335-3005.

Labels: conductive gasket, Conductive Rubber, EC-2040, EC-2130, emi gasket, emi gaskets, fluorosilicone, silicone, silicone sheet rubber, SNE-554, SNEF-60

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).

UL 94:
UL 94 quantifies/qualifies the flammability of polymeric components (rubber and plastics). This is important to prevent flame propagation in the event of a fire. UL94 has several levels of flame resistance. The most applicable to gasket and rubber materials are; UL 94 HB, UL 94 HBF, UL 94 V1 and UL 94 V0. The UL94 HB rating is a less stringent test where the specimen is exposed to a flame on a horizontal plane (UL 94 HBF relates to foam products). The UL94 V0 rating is a relatively aggressive test, where the specimen is oriented in the vertical position, it must self extinguish within 10 seconds and no flaming drips are allowed. Gasket and rubber materials that pass this test are considered to have very good flame retardancy.




UL 50:
UL 50 and UL 50E relate to ingress protection for electrical enclosures. NEMA and the IEC IP ratings are more common to the enclosure industry. While UL 50 does not follow these standards 1:1, the intent is very similar. A major separator of UL50 and the other enclosure ratings is that UL tests the gasket materials. There are no “NEMA gaskets” but there are various materials that will allow a NEMA enclosure to pass a particular test. UL has expanded this to offer UL50 rated gasket materials. A point of caution should be taken, while the materials may be UL50, UL50E rated, the enclosure and gasket designs are still major factors in passing the wash down requirements. Proper latching and gasket compression is paramount.

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. For more information about these material or other enclosure gasket materials, please contact Stockwell at 215-335-3005 or visit www.stockwell.com

Labels: NEMA gasket, UL 50, UL 508, UL 50E, UL 94, UL Gasket, UL Gasket Material, UL Rated Gasket, UL50 gasket, UL94 V0

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. Because the material is rolled up and supplied on a core it resembles a roll of tape. One of the most common consumer uses is weather stripping, used to reduce air leaks in windows during the winter months. While it would seem any gasket tape would suffice for a seal, the fact of the matter is that all materials are not created equal. This is especially true for commercial and industrial applications where NEMA, UL, or IP requirements need to be met. Often overlooked is long term performance; 1 year, 5 year, 10 year, etc... some material will perform well initially, however over time they will relax and take a compression set which can result in leaks and require costly field repairs.

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. These offerings take into consideration long term use, UV and ozone exposure, extreme high/low temperatures and firmness for compression. Included are materials listed by UL for UL50, UL50E (periodic recompression & continuous compression), UL197, UL508, UL 1571, UL1572, and UL94 V0. Also included are foams that meet 21 CFR 177.2600 suitable for food contact. This wide range of Gasket Tapes (or Strip gasket) allows Stockwell to supply gasket materials that will meet most enclosure gasketing needs .

An important design note about strip gaskets for enclosure gaskets is that for more aggressive wash down tests it is best to protect the gasket from a direct blast from the jets. In some cases the ends need to be bonded to eliminate ingress and the joint. Also, having a latching or fastening scheme that allows for even compression, hedges the chances for passing a NEMA or IP test. Stockwell’s Applications Engineers can help pick the best material for a particular test.

The base foams and sponges for Stockwell Strip Gaskets include, R-10470 closed cell silicone sponge, HT-800 closed cell silicone foam, F12, R-10450 reinforced silicone sponge, HT-870 open cell silicone foam, and 3M VHB foam tapes. These foam tapes / sponge tapes are stocked in pre-laminated lengths and held in master logs (typically 36” wide) ready to be slit to customer specified widths (e.g. 0.75”, 1”, etc...). Stockwell often makes custom gasket tapes by applying one of the many adhesives to foams or sponges not listed above. Materials like Poron urethane foam are readily made into foam tapes.

For more information about Gasket Tapes and Strip Gasket, please contact Stockwell at 215-335-3005 or visit stockwell.com.

Labels: dust Gasket, Foam Gasket Tape, Foam Tape, IP gasket, NEMA gasket, Poron gasket, Strip Gasket, Strip-N-Stick, Water gasket