Fastener Coatings and Corrosion Protection

Coating is chosen from exposure, not appearance

The most expensive coating on a dry interior partition is wasted money, and the cheapest one on a coastal roof is a callback. The decision starts with where the fastener will live and for how long.

Electroplated zinc

Clear, blue, yellow and black zinc are electroplated finishes. They give useful protection indoors and in sheltered positions. Colour is largely a passivation difference rather than a thickness difference, so yellow is not automatically better than clear.

Plated with wax

A wax topcoat over zinc plating reduces driving torque noticeably, which matters on dense board and on long repetitive runs.

Phosphate

Black and grey phosphate are light conversion coatings. They give modest corrosion protection and useful friction under a driver bit, which is why they dominate the drywall market. They are not a wet-area finish.

Hot dip galvanising

A thick metallurgically bonded zinc layer. The standard specification for external timber, fencing and ground-adjacent work. It is thick enough to affect thread fit, so it is specified at order stage rather than applied afterwards.

Multi-layer applied systems

Ruspert and Magni are multi-layer applied coatings rather than electroplating. They are specified where corrosion resistance has to exceed what plating can deliver without the thickness of hot dip galvanising, typically on roofing fixings and in coastal air.

Hydrogen embrittlement

High grade class screws that are electroplated need baking after plating. State the grade class when ordering any plated finish above class 8.8 so the process route includes it.