The Africa Desk of the International Zinc Association will present an expert webinar on galvanizing and zinc coatings on Wednesday 30 June at 14:30 in conjunction with Creamer Media. It will be presented by Simon Norton, in conjunction with Terry Smith, expert consultant on hot dip galvanizing and coated structures, and Weartech director Adam Wintle, who will cover zinc thermal spraying.

The webinar will specifically give insight into zinc-based coatings, particularly galvanizing, zinc-rich paints and zinc thermal sprays. Norton explains that engineering and technical staff often get confused over the various terms bandied about in South African industry such as ‘galvanized’, ‘cold galvanizing’ or ‘zinc-rich paints’. “Engineers also do not realise the potential for zinc thermal spraying in the repair and maintenance of exposed steel structures, repairing rusted rebar and coating ships,” says Norton.

It is metallic zinc in hot dip galvanizing that affords cathodic protection and barrier protection to galvanized steel. The extent of protection offered is directly proportional to the zinc coating thickness, while the zinc in zinc-rich paint provides cathodic protection by means of fine zinc powder dispersed in a dry film of paint resins. Zinc-rich paints need a high film build to provide adequate protection to steel and application technique is critical to prevent holidays in the coating.

A further factor to be considered is the environment to which these coatings are exposed. Paint coatings are notorious for having pinholes that allow the external environment to penetrate the coating, something hot dip galvanizing avoids. The key difference is that hot dip galvanizing results in the zinc coating forming a metallurgical bond with the underlying steel, whereas zinc-rich paints (cold galvanizing) merely adhere to the steel surface.

Zinc thermal spraying is a powerful tool for the engineer, and is applied by melting zinc wire or zinc alloy wire and spraying the surface of steel using special thermal spray guns. Provided the steel surface is properly prepared, and in combination with a zinc-rich primer paint and a top coat, a thermally-sprayed steel item can last for years. Wind turbine towers, for example, are zinc thermal sprayed and then overcoated with multiple organic coatings to provide long exposure life.

“This seminar will be a great learning opportunity for engineers in training and for practicing engineers who need to upskill,” comments Norton.

All registered attendees will receive a free subscription to Engineering News & Mining Weekly, as well as a free copy of the IZA’s Zinc Matters, which provides an overview of zinc primers.

To register for the webinar, visit: https://zoom.us/webinar/register/WN_f5w2-TUzSrC6jv1aPU87GA