Experts in Silicone Gasket Solutions
Experts in Silicone Gasket Solutions

Company History

Occasionally we hear comments from customers and vendors who are surprised that Stockwell Elastomerics is still privately held – and a 4 generation business that continues to operate independently in a dynamic marketplace.

We successfully operate the business in Philadelphia – with an interesting mix of diversity and culture in our workforce of over 100. Our commitment and the systems we have developed using Lean Business tools have enabled us to build a Rapid Customer Response system that we strive to have recognized as world class. We have more growth ahead of us – and we are committed to remaining in Philadelphia to benefit our dedicated staff who serve our customers with excellence and passion.

Come see us, meet our dedicated staff or contact me to learn more about what we are up to.

Bill Stockwell
Chairman/Majority Owner/Chief Technology Officer

Our First 100 Years

Stockwell Elastomerics 100 years logoStockwell Elastomerics is a fourth generation, privately held business founded in 1919 as a distributor of belting, hose, sheet rubber packing and wholesale rubber products by Frederick E. Stockwell. We have changed greatly over the years. Each succeeding generation has made its mark on the company, capitalizing on market opportunities, incorporating new products and capabilities and surviving the challenges that beset all small businesses.

Elbridge F. Stockwell became President of our firm in 1949. It was during the late 1940s when our firm adopted new materials and technologies such as Rubatex® closed cell neoprene sponge and silicone rubber products made in sheets from General Electric silicone compounds. These products helped our company penetrate the early aerospace, aircraft, color television and business machines markets of the 1950s and 1960s.

Elbridge F. Stockwell, Jr. became President of our firm in 1968, during the peak years of the space program. Silicone rubber components provided by Stockwell Elastomerics orbited the earth and landed on the moon. However, through the 1970s the Philadelphia industrial market matured, with many customers leaving the region for what was called the ‘Sun Belt’. Since many of these customers were the main users of our traditional hose, belting and rubber packing distributor product line – we decided to improve and expand our in-house die cutting and rubber molding production capabilities, and concentrate on the manufacture of gaskets, seals and cushioning components. This shift toward supporting Original Equipment Manufacturing (OEM) customers was a defining period in the history of the company.

William B. Stockwell became President of the firm in 1980. We relocated from a multi-story facility to our present location at 4749 Tolbut Street in northeast Philadelphia in March 1981, and continued to invest in new equipment for the custom rubber molding and fabrication operations. Significant investments were made in R&D and Process Development to support the Strategic Aerospace and Defense Electronics sectors throughout the 1980s. Conductive elastomers for ESD Protection, thermally conductive silicones and advancements in rubber molding technologies were keys to our success.

Stockwell Elastomerics transitioned once again in the early 1990s to commercial high technology applications – utilizing the silicone rubber materials technologies developed in the 1980s. Additional materials such as Rogers Corporation PORON® cellular urethanesBISCO® silicone foams, COHRlastic® (now NORSEAL®) silicone sponge and solid silicone and Specialty Silicone Products’ conductive silicones for EMI shielding enabled us to provide a broad range of solutions to the engineering community in our core markets. With the support of our strategic vendor base, our core competence truly became the fabrication and molding of silicone rubber and related high performance elastomers.

However, the global economy also dictates leaner operations and responsive production lead times. Recognizing this trend, Stockwell Elastomerics purchased the adjacent property (4773 Tolbut Street) in 1996 to facilitate further production capacity expansion. After a significant renovation, our custom molding operations were moved into the new facility in early 1997. With this added space, the company expanded into liquid injection molding of silicone rubber (LSR). The fast cure cycles of liquid injection molding enable fast-turn initial production of molded silicone rubber components from relatively simple single cavity molds.

In 2001, we invested in a Flow International waterjet system, to cut fast turn prototypes and initial production runs for innovative customers in the technology sector. With a properly scaled and dimensioned dxf file received in the morning, we developed capability to ship prototypes that night if the situation required. In 2002 we purchased a second waterjet system and in 2003 we purchased a third waterjet system. Interestingly, much of running time on the waterjet systems is consumed by production work, such as gaskets with very narrow walls and other features that cannot be die cut as well as they can be waterjet cut.

In 2003 Stockwell Elastomerics transitioned from ISO 9002:1994 to ISO 9001:2000. We have benefited greatly from using the structure of ISO to define processes and work flows to enable us to respond faster.

In 2005 Stockwell Elastomerics invested in a cryogenic de-flashing system to improve production throughput in our Liquid Silicone Molding operations. This has enabled us to provide precision molded silicone rubber gaskets and seals with nearly flash free parting lines. This reduces unit cost and lead times.

In 2006 Stockwell Elastomerics further expanded its product offerings in thermal management materials and electrically conductive silicones for EMI shielding. We continue to see our value increasing as a Materials Technology and Solutions Provider, instead of just a component parts manufacturer. We would welcome your input on this.

In 2009 Stockwell Elastomerics responded to the recession by continuing to build its capacity to respond to fast-turn production orders by purchasing its fourth waterjet cutting system and adding approximately 35% more floor capacity in its die cutting and assembly operations. This move has paid off as demand has increased significantly for the assembly, kitting and special packing services we provide. Stockwell Elastomerics also updated its quality management system from ISO 9001:2000 to ISO 9001:2008.

In 2010 Stockwell Elastomerics purchased additional liquid injection molding systems to increase responsiveness for customers who are experiencing shorter lead times due to the way the global economy has required more speed and agile production scheduling from each of us.

In 2012 Stockwell Elastomerics developed UV (light) curing capabilities to produce large silicone foam and silicone sponge gaskets with spliced corners. Our customers in the large outdoor enclosure and telecom base station market can now purchase large gaskets at a lower cost due to material usage savings.

In 2013 and 2014 Stockwell Elastomerics launched its Gasket TapeSilicone Foam and Closed Cell Silicone Sponge adhesive backed gasketing product line. Gasket Tape leverages one of the company’s core competencies – applying adhesives onto silicone rubber materials.

In 2015 Stockwell Elastomerics evaluated additional tool-less cutting methods and invested in Flash Cutting. Using programmable high speed knives and punches, gaskets can be kiss cut on the adhesive release liners, and include release tabs to allow for easier exposure of the adhesive backing during assembly.

In 2016, Stockwell Elastomerics again updated its quality management system from ISO 9001:2008 to ISO 9001:2015.

As we approached 100 years, we began to consider how to sustain as a privately held business and thrive by serving our customers in a global market. We took on the theme of Sustainability and Perpetuity. That led us to become an ESOP – and we transitioned 30% into the Stockwell Elastomerics Perpetuity ESOP Trust which was announced in October 2017. It was great to spread the ownership and rewards for our success.

Our fast-turn business model requires that we maintain a strong inventory position in our core materials, and by 2016 we needed more room to buy our silicone foam, silicone sponge and similar materials in higher quantities to protect our customers from shortages. In August 2017 we broke ground on an additional building which provides more inventory storage capacity, additional offices and a new gathering space so all 95 employees can be seated for company meetings.

Both 2017 and 2018 were solid growth years, which were made more challenging due to the global shortages in polysiloxane, the key ingredient in silicone rubber. Thankfully we got through that time by relying on vendor partners with close business relationships.

In 2019 we celebrated out 100 year anniversary on a beautiful day in October with a party under a tent in the backyard of the facilities. Many of our strategic material suppliers attended as well. It provided an opportunity to reflect with gratitude on those who came before us.

In March 2020, the COVID-19 pandemic impacted us in many ways. Stockwell Elastomerics was identified as an essential business, so we remained open throughout those initial days of uncertainty. Like every other business, we scrambled to understand the necessary hygiene, social distancing and other requirements required to operate safely. We shifted our product mix to fabricate silicone rubber manifold gaskets for a nationally recognized ventilator production build. There were 5 other ventilator programs we fabricated gaskets for, or provided adhesive backed silicone gasketing materials for others to fabricate. The pandemic required special collaboration within the gasket industry. There was pressure to perform and we responded.

In January 2021, Tom Rimel joined the company as our new President – the first time in the company’s history that a family member was not leading the company. Bill Stockwell assumed a new role as Chief Technical Officer to provide guidance on materials and to share his knowledge of applications and customers.

Beginning in April 2021, we experienced supply chain shortages in the silicone rubber industry that were worse than 2018. We learned a contributing cause was a constriction in the supply of refined silicon metal, an essential ingredient in poly-dimethyl siloxane – the backbone of silicone rubber. 2021 and 2022 were challenging due to these shortages. By the close of 2022, the bottlenecks in production and logistics were opening.

In 2023 we look to a bright future. Reshoring to North America in certain technology equipment sectors has begun. And we are strategically strengthening our Rapid Response business model to support the many new applications for high performance gaskets that will be required.


As a US-based custom gasket manufacturer looking to the future, Stockwell Elastomerics will dedicate our time and resources to improving the competitiveness of our best customers in the technology sector.

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