The primary application for impregnation is to seal castings against leakage of air, gases, and fluids.

Impregnation is also used to seal porosity for surface finishing.  Finishes such as conversion coating, plating, wet paint, and powder coatings can be applied after impregnation. 

Impregnating prior to these applications will alleviate blistering, spotting, and bleeding of pre-plating solutions through plated parts.

It will also eliminate "fish eyes" and pin holes in painted and powder coated components.