The draped figure of the Briggate Minerva, a 630kg sculpture by the prolific Scots artist Andy Scott, which is destined for a shopping centre in Leeds, emerges from a galvanizing bath at Highland Galvanizers and Colour Coaters.

The process, called hot-dip galvanizing, puts a zinc coating on steel, protecting it from corrosion for between 40 and 150 years, depending on the environment the piece is kept in.

Highland, a family-owned firm with plants in Cumbernauld and Elgin, has had a long relationship with the Maryhill-based sculptor, providing weatherproof and decorative coatings for some of his works including the 10m high, four-armed "metal mermaid" Arria, which sits by the A80 near Cumbernauld.

Geoff Crowley, managing director of Highland, which employs 90 people and last year saw pre-tax profits of £630,000 on a turnover of £8.2 million, said the firm is content to be "unsung heroes" supporting globally dispersed industrial and creative work from Scotland, including Scott's sculptures, some of which have gone to the US, Japan and Australia.

"The export drive is very much by others," Crowley said. "While we contribute to their success, we don't do 'front of house'."

Highland has achieved steady growth in recent years through its collaborations with thriving Scottish manufacturers and exporters such as Hugh Logan Engineering of Hamilton, which sells fencing to Bermuda, Surinam and Sudan, and Russell Play of Newbridge, Midlothian, whose playground equipment is selling successfully in France and Spain.

Founded in Elgin in 1978 to service the north of Scotland, Highland Galvanizers opened its second plant in Cumbernauld in 2002, operating under the name Highland Colour Coaters, which has pioneered new methods of applying colour to galvanized steel.

The firm's innovations include combining the galvanizing process with powdercoating – covering metal with a coloured organic coating that combines aesthetic appeal with durability.