Casting impregnation

A porosity sealing solution

Casting impregnation is the leading solution to porosity – the voids in metal components which occur during the casting process.

It can seal leak paths that would make pressure or fluid-tight parts otherwise unusable, improve the integrity of components, and creates an ideal surface for applying long-lasting surface coatings.

How does casting impregnation work?

Casting impregnation seals porosity by using a vacuum to remove air from the voids known as porosity and then fill them with a chemically and thermally resistant polymer.

First, components are subjected to a dry vacuum in an autoclave, removing the air from the porosity. The components are then immersed in liquid sealant and the vacuum is released, filling the voids with the sealant. Next, a cold wash removes excess sealant from external component surfaces. Finally, a hot cure cycle is used which polymerises the sealant, turning it from a liquid state to a solid polymer. 

To find out more about the impregnation process and watch our video in which each stage of the process is detailed, visit our vacuum impregnation process explained page.

Applications for casting impregnation

The applications of vacuum impregnation for porosity sealing span many industries, as porosity can be present in any cast component. Examples of applications include:

Automotive Powertrain Components e.g. cylinder head, cylinder block, transmission housing, EV battery housing, Electric Motor Housing

Braking systems

Air Conditioning Compressors

Electrical Components

Sinter Components

Additive Manufactured/3D Printed Components


Casting impregnation services, sealants and equipment from Ultraseal International

Ultraseal International is the global leader in porosity sealing, providing casting impregnation services, sealants and equipment to meet all manufacturing requirements. 

Outsourcing casting impregnation to one of our worldwide impregnation service centres is a popular solution for manufacturers with lower production volumes. Those with higher production volumes may wish to consider investing in vacuum impregnation equipment or opting for our fully managed onsite service. There are many considerations when making an investment in equipment; such as component dimensions and available system floor-space; whether the system is to be integrated into the existing production process or an off-line system; operator involvement; choice of component handling method; and operating and environmental cost factors. 

For more information about casting impregnation or guidance on the best porosity sealing solution for your business, please get in touch with the Ultraseal team.








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