Foam and Sponge Parts

Foam and sponge are extremely versatile materials which make them extremely useful for producing parts to service a wide range of applications. In this blog, we look at the types of foams and sponges which CRG uses to fabricate finished parts, as well as the types of applications these parts can service.

When talking about foam and sponge, it is important to note the difference between these two materials. Foam rubbers are created when, during the manufacturing process, a gas is blown into a liquid mixture, creating many small bubbles. This process results in a material which has many small, self-contained bubbles, much like what one sees with baked bread.

Sponge, on the other hand, can be broken down into two types: open cell and closed cell. Open cell sponge is produced when sodium bicarbonate is added as an ingredient to an uncured rubber mixture in a mold. The resulting effervescence creates a network of interconnected cells throughout the material – hence the name “open.” Closed cell sponges have a structure consisting of non-interconnected cells that contain air. These non-interconnected cells are formed during the manufacturing process when a gas (usually nitrogen) is introduced to create completely enclosed bubbles within the material.

Open cell vs. closed cell sponges

A key difference between open and closed cell sponges has to do with their compression set resistance – the degree to which the material resists taking on a permanent deformation when pressure or force is applied and then removed.

Due to the presence of the interconnected cells, open cell sponges are more breathable than their closed cell counterparts. Open cell sponges allow air under pressure to pass through them quickly; conversely, when the pressure is released, air is drawn back into the material, allowing it to rebound quickly to its original thickness.

With their non-interconnected cell structure containing air, closed cell sponges can take on a deformation when pressure is applied, squeezing air out of the cells. Depending upon the material, it may or may not rebound quickly to its original shape. Some closed cell sponges can take on a permanent deformation when pressure is applied.

Another significant difference between open and closed cell sponges has to do with moisture absorption. Open cell sponge will soak up moisture or liquid, only releasing it when the material is compressed. This makes it a good candidate material for applications where this property is required. Due to its lower absorption of moisture or liquids, closed cell sponge is preferred for those applications where maintaining structural integrity of the finished part is desired.

Foam and sponge: applications and parts

Parts can be cut from foam and sponge which service an array of industrial, automotive, and commercial applications. Depending upon the application, a wide range of foams and sponges made from different types of rubbers are available to provide the desired characteristics and properties. EPDM, Neoprene, Fluoroelastomer (FKM, also known as Viton®), Silicone, and microcellular urethane (Poron®) are some of the types of foams and sponges which CRG uses to service industrial and automotive applications. Examples of parts which CRG produces from foam and sponge materials include the following:

Automotive/mass transit applications

  • Gaskets and seals for engine and HVAC systems

  • Gaskets for electrical applications, including wiring and lighting

  • Parts for reducing noise, vibration and harshness (NVH parts)

  • Seals for vehicle doors, trunks, and enclosures

  • Filters

  • Seating

  • Trim

Industrial applications

  • Gaskets and seals for machinery and equipment

  • Gaskets and seals for wiring and lighting

  • Gaskets and seals for enclosures, receptacles, and containers

  • Parts for reducing noise, vibration and harshness (NVH parts)

  • Insulation

  • Filters

  • Acoustic applications


  • Seals for washers, dryers, dishwashers, refrigerators, vacuum cleaners, etc.

  • Gaskets and seals for air conditioning, heating, and other HVAC equipment/systems

  • Insulation

Construction applications

  • Construction Industry

  • Seals for building closures, including windows and doors

  • Seals for electrical boxes and control panels

  • Seals for building HVAC, lighting, and fire/security systems

  • Pipe wrapping

  • Expansion joints

  • Insulation

  • Acoustic applications

CRG has an experienced team at your disposal to help you choose the right foam or sponge material for your next project or application. From initial call to the finished part, CRG will support you every step of the way, offering technical support and advice on the best material for your specific application or assembly process needs.

Our advanced production capabilities allow us to produce foam or sponge parts in any quantity, shape or size. Parts can also be kiss cut or supplied with a pressure sensitive adhesive (PSA) backing applied. All parts are produced to customer specifications and requirements in our production facility certified to ISO 9001:2015.

To find out more about the foam and sponge parts we can produce, please contact our sales department at