Expansion Plugs

Original patent holder and manufacturer of the Welch Expansion Plug since 1913, M.D. Hubbard offers the widest range of sizes anywhere -- from 1/8"diameter up to 6"diameter. Expansion plugs and cupped plugs are an inexpensive, efficient, permanent method of closing/sealing manufactured holes in casting and other processes. Expansion plugs with a ground edge are available for applications requiring an exceptional degree of holding power or leak resistance.

Standard Materials:

• Steel: SAE1008/1010 low carbon steels ASTM#A1089 or A569 depending on gage
• Aluminum: 1100H14 to ASTM#B209
• Stainless Steel: type 302 to ASTM#A177 or type 430 to ASTM#A176
• Brass to ASTM#B36
• Customer specific materials different than those listed above are commonly run

Finish

• Steel: provided plain finish with a light oil. Expansion plugs can be provided with a wide range of coatings: mechanical zinc (processed in house), electro-zinc, black oxide.
• Aluminum: provided plain finish. Aluminum plugs are washed in a light mineral spirit in order to remove any solvents or residue.
• Stainless Steel: Provided plain finish. Stainless Steel plugs are washed in a light mineral spirit in order to remove any solvents or residue. Stainless plugs can be passivated.
• Brass: provided plain finish. Brass plugs are washed in a light mineral spirit in order to remove any solvents or residue.

Suggestions for Installing Hubbard Expansion Plugs