One of the most common uses of zinc is to coat plate steel to give it corrosion resistance. AFT Fluorotec’s zinc thermal spray process has many possible applications and to provide corrosion resistance to steel products is the most common.

This process is regularly applied to car chassis and architectural steelwork. However less well-known applications are the thermal application of zinc to window frames and this case, a huge steel roof lantern.

One of our regular customers for zinc spraying is a manufacturer of bespoke window frames and glass roof products. Recently they were commissioned to design and manufacture large windows and a whole glass roof for a premium house being built on the coast of Scotland.

Most domestic windows are made from PVC with a steel frame inside. The attraction of PVC being that it provides a thermal break, meaning the cold on the outside of the window frame doesn’t make the inside of the window frame cold too, siphoning off energy and heat from the home.

However, when it comes to bespoke structures that are windows forming the roof of a house, PVC isn’t going to cut it and metal materials are required. Steel is a great choice for fabrication as cutting, forming and welding are all straightforward. However, steel rusts.

Why not use aluminium?

Aluminium is only about 1/3rd as strong as steel, meaning the frames around the glass would have to be much larger than if made with steel, becoming intrusive into the line of sight and aesthetic appearance of the roof structures.

So steel is the choice but what about rust?

Corrosion in untreated external steel is impossible to stay on top of, no amount of painting and maintenance will keep the rust at bay – especially in a wet, salty coastal Scottish location.

The solution?

Zinc coats the frames which form the windows and roof. This means that they are corrosion protected and can be subsequently plastic coated with complete confidence that no corrosion is taking place on the structural roof frame, which is supporting 2 tons of glass in an impossible to inspect aspect.

Why choose thermally sprayed zinc coatings over zinc plating?

A couple of reasons. First is the sheer dimensions of these huge frames. Zinc plating such 3 dimensionally large fabrications would require an enormous capacity.

Secondly, there is the temperature. One of the primary benefits of thermally sprayed zinc versus traditional zinc plating is the temperature at which the process takes place.

AFT Fluorotec’s thermally sprayed zinc subjects the items being coated to much lower temperatures than traditional dip plating. For such a precise and relatively delicate fabrication as a complex roof lantern, keeping temperatures low is very important to prevent the structure warping and/or softening through suffering a heat cycle as the sections of the steel window frames are as small as they can possibly be and remain strong enough for purpose.

Back to the thermal break – don’t worry, our customer has clever technology within their product to deliver complete insulation. Get in touch with our team if you want to discuss our services.