What is an Expansion Plug?An expansion plug is a type of pipe fitting used to seal the end of a pipe. It is also known as an end cup and helps to prevent backflow. It gets inserted into the end of a tube and then expanded with a wrench or other tool to create a seal.

An Expansion plug fills the hole in a casting, manifolds, or other components to prevent the escape of fluids or gases. But how do they work? Read on to learn all about expansion plugs and how to choose the right one for your needs.

How Do Expansion Plugs Work?

Expansion plugs provide a permanent seal eliminating the use of O-rings, sealants, or threads. They work by expanding the metal diaphragm in the plug as it is set into place. The expansion of the metal creates a strong seal that can withstand high temperatures and pressures.

Expansion plugs have a cup-like shape with a metal diaphragm in the center. A threaded bolt is also in the center of the diaphragm used to expand the metal and create the seal. The bolt gets tightened with a wrench or any other tool to expand the diaphragm.

When the bolt gets tightened, it forces the metal diaphragm outwards and creates a seal against the inside of the pipe. You can remove the expansion plug by loosening the bolt and allowing the diaphragm to contract to its original size.

Expansion Plug Material

At Minneapolis Washer and Stamping, we specialize in the manufacturing of custom expansion plugs. We can create expansion plugs from a variety of materials, including:

  • Aluminum
  • Brass
  • Cold Rolled Steel (1)
  • Stainless steel
  • Nickel

We also provide finish options with materials such as:

  • Anodizing
  • Black oxide
  • Cadmium plating
  • Chrome plating
  • Powder coating
  • Zinc plating

Expansion Plug Application

Expansion plugs are most commonly used in the automotive industry. They seal transmission cases, differentials, oil pans, and valve covers. They are also essential in other sectors, such as:

  • Aerospace
  • Electrical
  • Plumbing industries

When choosing an expansion plug, it is essential to consider the pipe size or opening that needs to get sealed. Our expansion plugs are available in various sizes to fit most applications. We can also customize it to meet your specific needs.

With over 80 years of experience, Minneapolis Washer and Stamping is your one-stop shop for all your expansion plug needs. Our products are 100% US-made and of high quality. If you’re a resident or business in US, make sure to contact us for a free quote today.

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