Würth ZINK 300 Cold Galvanising Zinc Paint, 500 ml, 0892200

Würth ZINK 300 Cold Galvanising Zinc Paint, 500 ml, 0892200

Würth ZINK 300 (article number 0892 200) is a zinc paint for cold galvanising in a 500 ml tin, containing over 90% zinc powder pigments. The coating withstands temperatures up to +300 °C and gives the surface the appearance of hot-dip galvanised steel.

How cathodic protection works

Zinc paint is not simply silver-coloured paint. It protects electrochemically: zinc is more electronegative than iron, so when the two metals are in electrical contact and moisture is present, the zinc corrodes before the steel does. The steel stays protected even where the coating is scratched or pierced - the classic weak point of ordinary anti-corrosion paints, where every scratch becomes the start of rust creeping under the film.

That is exactly why a zinc content above 90% is decisive. For the protection to work, the zinc particles must be in continuous electrical contact with each other and with the steel. Too much binder insulates them from one another and the coating becomes ordinary paint that happens to be silver.

Surface preparation

The surface must be clean, dry and free of dust and grease. This is not the usual boilerplate from the label but a condition for the protection to function: any layer of paint, rust or oil between the zinc and the steel breaks the electrical contact and turns the coating into decoration. Remove old rust mechanically down to sound metal, and grease with a degreaser.

Film thickness and overlap

The recommended film thickness is 1.5 times that of hot-dip galvanising, and when repairing an existing coating you should allow a minimum 1 cm overlap onto the sound area. Coverage is around 250-350 g/m² per coat. For critical components, apply two coats.

Drying times

The coating is touch-dry after 15 minutes and gains strength after about 45 minutes. Full cure takes 2-3 days - until then the surface should not be loaded mechanically or exposed to standing moisture. Application temperature ranges from -20 °C to +40 °C, which allows work in cold weather.

Typical applications

Repairing damaged hot-dip galvanised coating after cutting, welding or drilling - the most common use, because that is precisely where the protection has been broken. Beyond that: weld seams, steel structures, fences and railings, scaffolding, trailers, guttering and ventilation components, and as a primer under a topcoat.

Safety

Work in a ventilated space or outdoors and avoid skin contact. The product is flammable - store away from heat sources and naked flame. Shelf life is 12 months when stored correctly, and the tin should be closed tightly after use: zinc paint is thick and skins over quickly on contact with air.

Technical specifications

Questions and Answers