Bird droppings and water-based car paints

Citation

Bean, J. (1998), "Bird droppings and water-based car paints", Pigment & Resin Technology, Vol. 27 No. 2. https://doi.org/10.1108/prt.1998.12927baa.002

Bird droppings and water-based car paints

Bird droppings and water-based car paints

For some time now there have been growing complaints from car owners that the caustic effect of bird lime when our feathered friends decide to dive bomb certain makes of cars is ruining the finish. Furthermore, it is alleged that this only happens on cars that are finished with water-based coatings. Cars with the more traditional solvent-based coatings seem to suffer no lasting effect once the bird droppings are removed.

This issue was recently highlighted on the BBC TV's programme Watchdog. Of the 40 garages the programme makers contacted, a third thought that the problem had indeed got worse with the switch to water-based coatings. Car owners seemed even more convinced. In fact Watchdog received some 700 calls about the problem with more than half thinking it was due to water-based coatings. Most complaints were about Renault (23 per cent), with Peugeot and Vauxhall receiving 17 per cent and 11 per cent respectively.

Watchdog commissioned Chris Bowden of the University of North London (not renowned for studies in coatings technology) to investigate this problem.

He tested a Renault Clio, leaving bird droppings on the bonnet for 40 hours.

The lacquer layer was pitted and swollen, but the paint layer and bodywork was unaffected. Al Clarke, head of communications for the Society of Motor Manufacturers and Traders was very reassuring ­ as you would expect. He said that this extra protective lacquer coat is there to protect the body from bird lime.

Renault has said that it was already aware of the problem and was looking into "toughening up" the paint. Vauxhall is working with the paint industry to increase water-based paints' resistance to bird lime attack.

Perhaps they might like to make note of my own researches. I live in a rural environment and park my eight-year old Citroën BX under a tree. On this tree roost wood pigeons, occasional pheasants and numerous small song birds, all using my car as a public latrine. I wash it off no more than once a week (perhaps the windscreen more frequently!) and the paint work looks as good as new. Perhaps it is the birds' rural diet: or more likely, the silver metallic finish used by Citroën eight years ago.