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What Is Porosity Sealing?

When metal or composite parts are manufactured through casting, molding, or 3D printing, small voids (called porosity) can form within the material. These leak paths compromise a component’s ability to retain fluids or pressure, leading to quality and performance issues.

Porosity sealing is the process of filling these internal voids. The most common and effective method is vacuum impregnation, which seals pores from the inside out. This process allows manufacturers to salvage components that might otherwise be scrapped while helping to prevent failures in the field.

What Causes Porosity in Manufactured Components?

Porosity most often develops during solidification, when trapped gases or shrinkage create voids in the material. There are two main types of porosity:

• Gas porosity. This type of porosity occurs when gases become trapped during pouring or melting.
• Shrinkage porosity. Shrinkage porosity develops when molten metal cools and contracts unevenly, leaving small cavities.

These defects are common in die casting, investment casting, and additive manufacturing. Even when voids are not visible on the surface, they can lead to leaks, corrosion, and cosmetic flaws. Problems frequently emerge after surface finishing, when coatings such as plating, paint, or powder coat blister or fail to adhere due to moisture or air inside the pores.

How the Porosity Sealing Process Works

At Godfrey & Wing, porosity sealing is achieved through vacuum impregnation. The process begins by placing the part in a sealed chamber. A vacuum is applied to remove air from the internal pores, creating space for sealant. The sealant is then introduced under pressure, fully penetrating the voids. Afterward, the part is removed and the sealant is cured, forming a permanent, impermeable barrier.

This method effectively seals both blind and through porosity without altering the part’s dimensions or material properties. Because the process preserves structural integrity, manufacturers can reliably salvage high-value parts rather than discarding them.

Benefits of Porosity Sealing: From Performance to Profitability

Porosity sealing provides a range of key benefits, including:

• Enhances product quality and prevents gas or fluid leakage
• Salvages parts that would otherwise be scrapped, improving yield and lowering production costs
• Provides the reliability and safety required in industries like automotive and aerospace, where even a single leak path can affect performance
• Ensures proper adhesion of coatings such as anodizing, plating, painting, and powder coating by removing trapped gases that cause blistering
• Reduces returns related to leakage or cosmetic defects, protecting brand reputation

By addressing porosity early, manufacturers safeguard product quality, customer trust, and profitability.

Why Choose Godfrey & Wing for Porosity Sealing?

Porosity sealing is essential for eliminating porosity in cast, molded, or 3D-printed parts. As a global leader in this technology, Godfrey & Wing provides vacuum impregnation services and systems trusted by top OEMs in automotive, aerospace, medical, and energy sectors.

We offer flexible solutions, from stand-alone systems to fully automated production-line integration, backed by unmatched reliability and technical expertise. With more than seven decades of industry experience and a commitment to continual improvement, we help manufacturers meet the most demanding performance standards. At Godfrey & Wing, we don’t make your bad castings good; we make your good castings better.

Contact us today to discuss your porosity challenges.