Galvanizing

Galvanization, or galvanisation, is the process of applying a protective zinc coating to steel or iron, to prevent rusting. The items are first dipped into a bath of hydrochloric acid which removes any trace of rust or mill scale. Then re-dipped at a higher temperature in molten zinc, when removed a layer of molten zinc is formed on the top of the alloy layer,(termed free zinc), which gives off a silvery appearance. This can be left unpainted if desired, but weathering will dull down the appearance. Galvanizing protects in two ways:

It forms a coating of corrosion-resistant zinc which prevents corrosive substances from reaching the more delicate part of the metal.

The zinc serves as a sacrificial anode so that even if the coating is scratched, the exposed steel will still be protected by the remaining zinc.

Before painting, the galvanised product is thoroughly cleaned and surface prepared by removing any excess galv runs and sharp edges. The surface is keyed and cleaned, then a coat of etch primer followed up by four coats of top gloss or satin finish.