Metallising is a technique for surface-treating steel constructions not suited for hot zincing. This may include constructions that are too large for the zinc bath or types of steel not suited for hot zincing.
The constructions are cleaned through air blow cleaning. This gives the steel a rough surface, increasing the attachment, strength and life of the metallisation. Stainless steel and aluminium can with advantage be air blow cleaned.
During metallising zinc is applied to the construction using an electric arc, as with spray painting. This is done at 5,500° C.
A limitation of metallising is that it requires physical access to the construction throughout the process. On the other hand, it is possible to apply the zinc in the required thickness. As opposed to hot zincing, metallising involves no reaction between the metals or metallic attachment of zinc to steel.
Following metallising, the construction may be painted, increasing its protection against corrosion.