Air spray clears the paint mist

A low-pressure spray gun that can apply a 1mm thick layer of paint to an oil rig or a 0.02mm coating to a jet airliner is set to replace conventional paint spraying systems. It dramatically cuts pollution problems caused by paint mist and reduces the need for extraction systems.

The gun, developed in Scotland by Marlin Systems, operates at 1-5psi to deliver paints with a solids content as high as 85%. It will transfer 96% of the paint to the target.

Conventional airless systems run at around 3,000psi but have a transfer efficiency of around 30% because the high pressure atomises the paint into a high energy mist, dispersing drops over half a mile. Marlin Systems’ managing director Jim Lindsay, who developed the system, says techniques have hardly changed since the Second World War.

Marlin’s gun can spray a 40ft sea container using just 6 litres of paint – a third of the quantity required by airless systems. If a paint will flow out of its can under gravity, then the Marlin system will spray it, says Lindsay. It may look like treacle, but 5psi can be enough to move it through to the spray nozzle. Air at 20-50psi then creates a vortex to transfer paint onto the target.

Earlier this year, Marlin opened a factory in Irvine to start volume production. Orders have been received from shipyards faced with a ban on airless systems because of paint drifting onto houses and cars. Railtrack has ordered one to paint the Forth rail bridge. And the Blackpool Tower is getting one too.