By far the most common and well known application for our vacuum impregnation services is in sealing ferrous and non ferrous components against leakage of gas, air and fluids.
Other applications however, include:
Pre and post treatment for surface finishes
Micro-porosity voids tend to trap air, moisture or any other fluid to which they are exposed as well as allowing leak paths through the metal.
Fluids absorbed into the porosity of components during pre-treatment can ‘leach out’ during and after surface treatment, discolouring plated, anodised or alochromed parts and blistering paint or powder finishes. The ‘leaching out’ process is often accelerated by heat. This breaking of surface treatments can become even worse when the parts are exposed to corrosive environments. The existence of these open voids provides a ready made path for corrosion enabling it to attack the body of the component, dramatically reducing its lifecycle.
Vacuum impregnation can effectively seal (fill) micro-porosity voids in components before and after surface treatments.
Sealing to allow successful surface treatment
Vacuum impregnation with thermo-curing methacrylate sealant technologies is simple and extremely cost effective. It seals porosity up to the surface of the metal leaving the exterior of the component perfectly clean, unaltered in physical appearance, and ready for finishing treatments.
Improving bond strength and corrosion resistance of finished components
Micro cracks and porosity inherent in hard chrome plating and anodic films can allow fluids to penetrate the finished surface and promote corrosion ingress. Vacuum impregnation can seal the subsurface of the plating of anodic film, improving the mechanical bond strength and preventing corrosion.
Vacuum impregnating components which contain inserts and sleeves not only seals the assembly, it also improves the bonding of the insert. Most successful in sealing gaps of less than 0.13mm, it should ideally follow dry press fitting.
Brazed and welded assemblies (including complex radiator cores)
Even the best brazed or welded components can contain micro-porosity that allows leakage under pressure. Quite often these joints cannot easily be re-worked or locally sealed because other processes have masked the affected area. Vacuum impregnation using water miscible sealants allows us to quickly treat the whole component, wash excess resin from surfaces and internal galleries before curing for a life-long seal.
Entrapping or preventing sub-surface contamination
It’s difficult to avoid contaminating porous materials during manufacture. Porous castings absorb cutting oil during machining, while sand castings may retain particles of sand. Problems can develop later if these contaminants bleed out; particularly where parts must be kept exceptionally clean, for example in computer disc drives, food processing or pharmaceutical applications. Vacuum impregnation is used to either entrap or exclude trace contaminants and eliminate these problems.