Friday, April 23, 2010

This blog has moved

This blog is now located at
You will be automatically redirected in 30 seconds, or you may click here.

For feed subscribers, please update your feed subscriptions to

Monday, March 08, 2010

Wind Turbine Blade - Transportation Cushioning Pad

Cast liquid silicone rubber sheet materials have the tendency to grip smooth surfaces - especially table tops and similar work surfaces.

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. Wind Turbine Blade damage can be an expensive problem, not just from the cost to repair the blade, but also from downtime and installment delays in bringing the units on-line.

After several iterations, we developed a combination of closed cell silicone sponge cushioning with a 'grippy' liquid silicone rubber coated fiberglass cloth surface lamination.
The result has been a soft holding pad with enough tensile strength to cradle the blade as it is transported to the installation site. We have been told the blade damage has been reduced by 40% when our transportation cushion pads are used.

Closed cell silicone sponge was selected for the cushioning layer due to its low compression set and age, sunlight and weather resistance in prolonged outdoor conditions. The closed cell silicone sponge can be laminated to virtually any thickness using silicone based bonding adhesives. Closed cell silicone sponge is available in 3 grades of firmness - soft, medium and firm. The grippy LSR coated fiberglass has the same inherent age resistance - making this laminated construction a great example of how Stockwell Elastomerics can develop a combination of properties to solve an engineering challenge.

Tuesday, February 02, 2010

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. Silicone is a naturally heat resistant rubber, however without enhanced chemistry it is capable of burning in the presence of a flame. R-10400 may be used similarly to standard silicone sponge products such as enclosure gaskets, soft gasket, vibration dampening, environmental gaskets, and water sealing but also for application such as military and electronics that require a UL94 V0 flame rating or flame resistance.

Description: Flame Resistant Closed Cell Silicone Sponge Rubber
Put up: Silicone Roll or Silicone Sheet
Temperature Range: 100 – 500°F (-73 – 260°C)
Force Deflection: 10psi (@ room temp)
Compression Set: 10% (22hrs @ 212°F)
Thermal: Thermal Insulator, .02 W/m-K
Electrical: Electrical Insulator, Volume Resistivity 8E15 Ohm-cm
Flame Rating: Flame Retardant Rubber, UL94 V0
FDA Rated: 21 CFR 177.2600

Other properties such as UV resistant and a wide functional temperature range, makes R-10400 an ideal product for outdoor gasket and electronic enclosure gasket applications, where performance is paramount. Stockwell offers a wide range of adhesive backings (peel and stick) for ease of installation.

For more information on R-10400 flame resistant silicone sponge or other UL94 flame rated products, please call (215) 335-3005 or email

Labels: , , , , , , , ,

Friday, January 08, 2010

Conductive Pad, ESD Pad, Conductive Adhesive – Cryogenic Exposure

SE65 is a carbon filled electrically conductive silicone rubber with a durometer of 65 on the Shore “A” scale. SE65 is typically used to dissipate or more specifically 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). Bonding SE65 with RTV-CON makes a very intimate and strong bond when the surfaces are prepared properly.

Silicone has a general operating temperature ranging from -100 to 500°F (some grades vary). The SE65 has a conservative rating of -65 to 400°F. As a very crude test to see if there would be any deterioration of the SE65, RTV-60-CON or the bond between surfaces, a test piece bonded to aluminum was run thru Stockwell’s cryogenic deflasher, removed and hit with a hammer. The attached video clip shows the machine in idle mode set to -80°F (run mode). The sample was tumbled at -80°F for 60 seconds, removed and hit. There was no indication of bond or material degradation. This was a very crude test but does offer some insight to how well the bond holds up.


Stockwell Elastomerics carries a comprehensive line of ESD and EMI conductive silicone sheets, roll goods and molding compounds. For more information about these products, please call 215-335-3005 or email at

Labels: , , , , , ,

Monday, December 21, 2009

Silicone Materials Selection Guide Updated

Stockwell Elastomerics updated Silicone Materials Selection Guide - a comprehensive guide offering insight on the properties and benefits of using silicone for gasketing, sealing, and cushioning applications. This guide details Stockwell Elastomerics’ silicone rubber materials offerings in closed cell silicone sponge, cast silicone foams, gum based solid silicone and liquid based solid silicone. In addition, many common pressure sensitive adhesives offerings and product-enhancing surface lamination options for silicone foam and silicone sponge rubber are listed. This updated Silicone Materials Selection Guide is a quick “go-to” reference for engineers and designers. Silicone has become the material of choice by engineers for critical gasketing and cushioning applications. This can be attributed to its wide operating temperature range, resistance to compression set (good memory), UV resistance and long life.

Stockwell Elastomerics offers fast-turn prototyping for most silicone materials, often utilizing its extensive water jet cutting capabilities to produce cut to size parts from customer supplied CAD files.

To Request a Copy of the Silicone Materials Selection Guide
Download it directly from or contact Stockwell Elastomerics by phone (215) 335-3005 or email to request a printed copy.

Stockwell Elastomerics’ core competence is the fabrication and molding of silicone rubber and similar high performance elastomeric materials. Stockwell’s in-house capabilities include water jet cutting, custom molding, die cutting, and adhesive lamination. For more information on Stockwell Elastomerics’ offerings in silicone rubber, silicone sheet, molding and fabrication capabilities call (215-335-3005) or email

Labels: , , , , ,

Tuesday, November 03, 2009

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, call 215-335-3005 or email

Labels: , , , , , , ,

Monday, October 26, 2009

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 or call 215-335-3005.

Labels: , , , , , , ,