Galvanising steel is a process for coating steel with zinc, to prevent corrosion. Two types of process are used, electrically deposited zinc if (Zintec) and hot dip galvanised. Electrically deposited zinc is a continuous process for sheet steel. Special fabricating processes are needed during manufacture and repair of vehicles because of zinc's lower melting point. Production line processes use modified pretreatment then conventional paint systems.

Repair systems require modified body fillers and the need for approved painting systems, normal polyester spray fillers and fillers react with the zinc and in time crystals form from the zinc and the paint can fall off.

Alkyd based paints, similarly, react with zinc, a process known as supponification (producing soaps), forming white crystals and loss of adhesion. The process can happen with alkyds applied over suitable etch primers where, with time, reaction occurs between alkyd and zinc.

Hot dip galvanised steel is recognised by the large crystoline pattern on the surface of the steel and as the name implies, the steel is immersed in a bath of molten zinc. But in order to get the zinc to stick well, there is a flux floating on the molten zinc. This sticks the zinc and steel as an article enters the batch, but also coats the article as it is removed. This flux will not allow good adhesion of paint and should be removed. This can be achieved with Mordant solution, mechanically abrading or weathering for a year or two. The clean zinc will then require appropriate paint systems.