UNDERNEATH THE ARCHES
QThe wings of my Rover P5B were removed and blasted back to bare metal to remove all rust. Following several coats of anti-corrosion primer they have now been finished in body colour. I was planning to coat the underside with ‘schutz’ and then follow that with plenty of underbody wax. However, a friend suggested they should be coated with stone-chip instead, as it would be more resistant to damage from debris thrown up by the wheels. He also thought that underbody wax would not be durable enough to offer long-term protection. Do you have any advice? Roy George, Worthing
A‘Schutz’ (German for ‘protection’) is a rubberised bitumen-based coating that’s sprayed or brushed on to give a thick, black protective layer. Stone-chip is a Pvc-based coating that’s sprayed on and can be over-painted. Both of these are ‘permanent’ finishes. Underbody wax is a fairly thin semi-permanent coating that should be renewed annually in the high-impact areas around the wheelarches, and similar. It repels water, creeps into gaps and actively prevents corrosion.
Schutz or stone-chip protect the metal’s surface and also silence the constant noise of small stones and debris being thrown against the underside. A disadvantage of both is that, once damaged, water may penetrate a long way under the coating and cause extensive corrosion.
Use stone-chip if you want to paint the wheelarch areas body colour. Use cheaper Schutz if you don’t. In either case, an annual inspection and a coat of underbody wax would be a good idea.