Expansion Plugs
Secure your assembly with American-made precision. Seastrom Manufacturing stocks high-quality expansion plugs designed to permanently seal manufactured holes in castings, housings and assemblies. Whether you need small-quantity support for prototyping (10-20 pieces) or scalable volume for mass production, we offer immediate availability and short lead times without the burden of high minimums.
Types of Expansion Plug Caps
We offer two primary styles to meet your specific industrial sealing requirements:
- Concave expansion plugs (Welch style): These efficient components are ideal for limited-depth holes that require a counterbore and a permanent seal. They're available in aluminum, brass, cold-rolled steel and stainless steel (301-304).
- Tapered cup expansion plugs: We designed these robust dome plugs for applications that do not require a counterbore and must withstand significant pressure. We stock them in brass, aluminum, cold-rolled steel and stainless steel.
Material and Finish Options
We can customize our expansion plugs with a variety of finishes, including black oxide, cadmium, nickel and zinc. Visit our material and finish specifications page to confirm compatibility with your engineering standards.
Our commitment to flexibility and convenience has earned us a reputation for meeting and exceeding client expectations. We have consistently produced high-quality products for nearly 100 years and continue to deliver exceptional workmanship every day.
Why Choose Seastrom?
With nearly 100 years of manufacturing expertise, Seastrom is a trusted assembly hardware manufacturer for the aerospace, defense and commercial industries. Our ISO 9001 and AS9100-certified processes ensure every part meets rigorous compliance standards, such as DFARS, REACH, RoHS and Nadcap.
Contact us to request an industrial plug cap quote today.