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  • What is Porosity?

What is Vacuum Impregnation and how does it work?

Resin impregnation is a method of sealing porous materials without impacting on the functional or dimensional characteristics of the material.

Impregnation has been in commercial use for over 60 years and continues to be the preferred method for ensuring pressure tight components in failsafe applications.  The aviation, automotive, food processing and oil and gas industry use vacuum impregnation to improve the quality of their base castings, conserve resources and reduce scrap.

Impregnation is not only effective for preventing leaks, it is also an excellent pre-treatment for surface finishes.

Thermal cure sealants are not normally affected by materials such as iron, bronze, aluminium, ceramic, GRP and carbon. In fact any inert material that is porous can be impregnated.

Vacuum Impregnation

The vacuum impregnation process, in its simplest form, is made up of four "key" stages:

• Evacuate porosity with deep vacuum - fig 1
  
• Fill porosity by flooding the part with sealant and applying pressure- fig 1
  
• Remove residual sealant from the part - fig 2/3
  
• Catalyze (change to solid) sealant inside porosity - fig 4

Internal Pressure Impregnation

The pressure impregnation process uses the casting itself as the pressure containing vessel and is primarily applicable to large castings. The resin fills the casting and pressure is introduced to force the resin into the microporosity.