Engineering news
Technology from the oil and gas industry is being used to help paint the Forth Bridge in the hope that the work will not need to be carried out again for decades.
A special paint system is being used to coat the 119-year-old structure, which, it is claimed, will protect it from rust for at least 25 years and possibly longer.
Balfour Beatty has been restoring the bridge since 2002 by blasting the 53,000 tonnes of steelwork down to bare metal before repainting it. The glass flake epoxy formula employed has previously been used to protect oil rigs and is being supplied by Bolton paint manufacturer Leigh Paints.
Carl Burrell, coatings manager at the company, said: “It essentially binds with the metal to stop moisture getting through. Guarantee is a strong word – but yes, there is a warranty for 25 years.”
The bridge, which carries the East Coast Main Line across the River Forth, will require 500,000 litres of paint. It was the first bridge to be built entirely of steel and is still the longest cantilever railway bridge in the world.
“The paint system has been around for a few years but has primarily been used in the offshore industry,” said Burrell. “The bridge has always been treated but as time has progressed, new technologies with a longer shelf-life have emerged.”
The paint system consists of a blast primer, an epoxy glass flake build coat, and an acrylic urethane finish, as well as a stripe coat of epoxy glass flake.
The glass flake epoxy system was selected because of its adhesive and anti-corrosive properties.
Leigh Paints is also supplying paint to the site of the 2012 Olympics and London’s Tower Bridge.