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Casting Impregnation / Vacuum Impregnation

What is casting impregnation?

When parts are created by casting metal, tiny defects are nearly impossible to avoid. Whether those defects involve porosity of the surface, bubbles or other types of incursions, they can negatively impact a part's performance under operating conditions. Chemicals used in finishing parts can become trapped within the porosities and leak out during subsequent processes or operations. Air leaking from the porosity in aluminum or other materials can interfere with the proper curing of paint or other finishes.

Even if the imperfections do not affect the part itself, they may allow gases or fluids to escape through microscopic leak paths in the wall of the casting, contributing to premature component or system failure in the field.

Introducing a sealing resin into the areas of porosity through one of the vacuum impregnation processes can provide sealing, reduce moisture and internal corrosion and enhance the integrity of the part.

Three types of vacuum impregnation methods

Cardinal Metal Finishing can accommodate all of your casting impregnation needs, eliminating porosity in aluminum and other metal castings. We offer three different types of vacuum impregnation processes, so we can select the process that best fits your needs and budget.

  1. Dry Vacuum Pressure Impregnation
    • Dry Vacuum Pressure Impregnation uses two process tanks for high production quantities. No liquid is present during the initial vacuum stage to interfere with gases being pulled from the pores. This process can be utilized to remove moisture entrapped in pores, which would otherwise remain behind as a contaminate. Dry Vacuum Pressure processing is the most robust process type whenever there is fine or variable porosity to be sealed. This process can also be best for applications requiring higher production volumes. Meets all Mil Spec process requirements.
  2. Wet Vacuum Pressure Impregnation
    • Wet Vacuum Pressure Impregnation requires only one process tank. Parts are submerged in the sealant and the vacuum is applied to the parts and sealant simultaneously, followed by pressurization with air.
  3. Wet Vacuum Impregnation
    • Wet Vacuum Impregnation is the simplest and fastest vacuum impregnation process, in which the resin is introduced into the porosity at atmospheric pressure. No pressurization is used.

In all cases, the sealant cures inside the part, preventing leakage of gases and fluids. Residual sealant on the part's surface is carefully cleaned.

To ensure consistent high quality and prevent sealing resin bleed out and contamination (which are associated (only) with heat-cure resins), we use Loctite Resinal RTC. This anaerobically curing resin, which cures at room temperature, meets the requirements of Mil-I-17563C and Mil-Std-276A, along with most automotive casting impregnation specifications.

At Cardinal Metal Finishing our impregnation systems use state of the art monitoring controls to assure that our customers sealing needs are constantly met or exceeded. Our comprehensive preventative maintenance system ensures our equipment performs efficiently to meet your specifications. We conform to all applicable SAE standards.

Learn more about Vacuum Impregnation.

 impreg tank 1
 impreg tank 2
impreg tank 3