How to Select the Right Rubber Component for Your Application

Rubber Spacers, Rubber Washers, Rubber Gaskets – What’s the Difference?

It’s not uncommon to hear the terms “spacer,” “washer,” and “gasket” used interchangeably. However, these terms do not refer to the same thing. Although the differences between these components may seem subtle, it’s important to familiarize yourself with the distinctions so that you are better equipped to purchase the right parts for your application. Here, we will consider the distinctions between rubber washers, rubber spacers, and rubber gaskets, as well as why these distinctions matter in practice. We will also provide general guidelines about how to choose between rubber washers, spacers, and gaskets in your application.

At Thomas A. Caserta, Inc., we supply premium rubber components in all three of these categories, including custom, end-to-end manufactured parts for diverse industry clients. If you have questions about whether washers, gaskets, or spacers are more appropriate for your application, Caserta’s expert team can provide individualized guidance.

Rubber Washers

Rubber washers sit in between a fastener and its surface to ensure even weight distribution and protect the surface from vibration and friction. Although washers can vary in thickness, shape, and density, they typically take the form of solid rubber rings with a central hole for the fastener.

Fasteners exert a great deal of pressure to hold components together. Unfortunately, when pressure remains concentrated at a single point, that point experiences extra stress that can lead to premature wear. This concern is heightened if the fixture point has an irregularly shaped surface, which can induce vibration along the uneven contact points.

Rubber washers are designed to address all of these problems: by smoothing the surface between the fastener and the surface, rubber washers distribute the force more evenly, minimizing the risk of premature wear. Washer seals also increase tension across this wider area, which results in a more secure hold. Rubber washers, in particular, can also help seal against moisture, protect against leaks, and dampen external vibrations.

Applications of Rubber Washers

Given the ubiquity of fasteners in construction and manufacturing, washers are useful in practically every industry. Rubber washers, in particular, are the most useful in settings where moisture or chemical exposures are a concern. These demands are common in markets such as:

  • Medical devices (using FDA-approved elastomers)
  • Food and beverage (using FDA-approved elastomers)
  • Consumer goods and home appliances
  • Naval and marine
  • Aerospace

Benefits of Rubber Washers

In general, washer seals increase fastener effectiveness and prolong a product’s working life. At Thomas A. Caserta, Inc., we specialize in hard rubber washers, which offer several key advantages over metal, plastic, or soft rubber washers, including:

  • Heightened abrasion resistance
  • Resistance to common industrial chemicals
  • Improved pressure distribution
  • Protection against moisture and leaks
  • Excellent impact and crush resistance

Rubber Spacers

Rubber spacers are dense rubber components used to maintain distance between two surfaces. Within a larger assembly, they can be used to separate surfaces and prevent friction, insulate against electrical flow, or retain a specific configuration. On the exterior of a heavy or abrasive product, they can also serve as bumpers or protective pads. For instance, a dining table might have rubber spacers on the bottom to protect hardwood floors.

Rubber spacers are often conflated with washers. However, spacers differ from washers in that their primary purpose is to separate components rather than draw them more securely together. Spacers may be used independently between two surfaces, mounted on shafts, or adhered to a product’s exterior.

Applications of Rubber Spacers

Rubber spacers are highly versatile components. Depending on their size and construction, they can either separate and cushion components within an assembly, or provide clearance between a product and an installation surface. As a result, silicone spacers are used in a variety of diverse applications. Fastening applications that benefit from rubber spacers are often found in the following industries:

  • Electronics and electrical products
  • Telecommunications
  • Furniture and home goods
  • Manufacturing
  • Construction

Benefits of Rubber Spacers

Rubber spacers simplify assembly and help protect metal components from wear. Our hard rubber spacers offer a number of key advantages, especially compared to general-purpose washers. Benefits include:

  • Compact, dense construction with excellent impact resistance
  • Insulation against electricity
  • Resistance to moisture, chemicals, UV rays, and ozone
  • Customizable size and texture
  • Vibration dampening

Rubber Gaskets

Rubber gaskets are flexible sealing components that are typically compressed between two surfaces to prevent leakage. Although some gaskets closely resemble washers in shape, gaskets are commonly custom-cut to irregular shapes, including through-holes for multiple fasteners when necessary. These custom forms allow rubber gaskets to seal mating surfaces of all kinds, regardless of irregularities.

Gaskets are primarily used to prevent leakage, so they must be able to fill gaps between diverse mating surfaces. Rubber is the ideal material for these sealing applications, combining flexibility with strength and durability for a rugged, lasting seal. Rubber gaskets also dampen vibrations to further protect components in industrial environments

Applications of Rubber Gaskets

Gaskets can prevent leaks in engines, ducts, doors, and electrical enclosures of all kinds. As such, they are used across industries, with clients commonly coming from the following sectors:

  • Oil and gas
  • Aerospace
  • Naval and marine
  • Transportation
  • Consumer goods and home appliances
  • Manufacturing

Benefits of Rubber Gaskets

At Thomas A. Caserta, we manufacture rubber gaskets to any size or tolerance requirement. Our rubber gaskets protect critical equipment from damage due to moisture or vibration. Specific benefits of rubber gaskets include:

  • Resistance to ozone and UV light
  • Ability to withstand extreme temperatures, both low and high
  • Resistance to a wide range of chemicals
  • Vibration dampening
  • Low cost

Breaking Down the Rubber Sealing Products

In summary, the primary purpose of each rubber component is as follows:

  • Rubber washers are designed to distribute the pressure exerted by a fastener and protect the underlying surface.
  • Rubber spacers are intended to permanently keep two components from contacting one another.
  • Rubber gaskets are specifically engineered to create a lasting seal between two components.

In practice, these parts do resemble one another, and it is sometimes possible to substitute one for the other. For instance, using washers as temporary spacers is especially common. However, choosing a sub-optimal component can lead to premature wear on the rubber parts or on the surfaces themselves. It is better to use components as intended and to seek out specialized components to serve different functions.

When to Use a Rubber Washer

In general, you should consider a rubber washer in any of the following scenarios:

  • you want to prolong the working life of any fixture that uses a bolt or screw
  • the fastener in your product has an irregular shape that might induce vibrations
  • your application involves condensation or moisture that might damage a metal washer
  • you need to protect a fastener and surface against excess vibration

When dealing with fasteners, rubber washers provide extra tension and protect to some degree against wear, vibration, and leaks. If your primary concern is sealing, however, consider a gasket instead.

When to Use a Rubber Spacer

Most of the time, you should opt for a spacer whenever your primary goal is separating two elements. Washers often wear too quickly for this use case, and gaskets lack the necessary density. Spacers are dense, durable, and precisely the size your application requires.

When to Use a Rubber Gasket

A gasket is the most appropriate choice in the following circumstances:

  • it is critical to prevent any leaks between two surfaces
  • your components form an incomplete or irregular seal that could be filled with a flexible material
  • you need a non-standard rubber shape to fit between components

Gaskets offer the perfect combination of strength and give to create lasting seals between a variety of surfaces. Washers or spacers, by contrast, may lack the necessary flexibility for a tight and reliable fit.

Custom Engineered Rubber Parts from Caserta

Choosing a purpose-built rubber part is the best way to ensure your product performs well and holds up over time. At Thomas A. Caserta, Inc., we draw on advanced rubber manufacturing techniques to create custom washers, spacers, and gaskets for clients from across industries. We work with clients to select the optimal component type and material, with typical options including EPDM, Neoprene, Nitrile, SBR, Silicone, and Viton®.

For more information, or to get started on your custom spacer, washer, or gasket solution, contact us today.