All our bumpers are made of 304 stainless steel, at least 2 mm thick, mirror-polished. These are not catalogue options: they are the three parameters that decide whether a bumper still looks good after twenty years or starts to dull by its third winter. Here is why.
Why 304 stainless steel and not another grade
304 stainless steel (European standard X5CrNi18-10, also known as 18/8 or 18/10) contains around 18% chromium and 8 to 10% nickel. The chromium forms an invisible oxide layer on the surface, a few nanometres thick, which rebuilds itself as soon as it is scratched: this is what makes the material stainless all the way through, not just on the surface like chrome plating. The nickel provides the ductility needed to press and form deep curves without cracking, and the brightness when polished. It is the alloy of professional kitchens, dairy vats and boat deck fittings: it withstands water, frequent washing and road salt.
The cheaper 400-series grades (430, for example) contain little or no nickel: they polish less well, form poorly and can rust on the surface near the sea. They are found on cheap reproductions, and can often be spotted with a magnet, which sticks firmly to them, whereas it barely holds on annealed 304.
Why 2 mm
An original chromed steel bumper is generally 1.5 to 2.5 mm thick. A thin reproduction, in 1.2 or 1.5 mm, is lighter and cheaper, but it marks at the slightest pressure, vibrates, and mirror polishing reveals every ripple in the sheet. At 2 mm minimum, the blade has the rigidity of the original part, takes a parking knock without deforming, and has enough material to be re-polished several times over its life without thinning.
Why mirror polish
Mirror polish is not just about looks. A polished surface has fewer micro-reliefs where water and deposits can sit: it gets dirty less, cleans faster and the passive layer rebuilds evenly. It is also the finish that looks like the original chrome: from a metre away, you cannot tell the difference. Polishing is done in several passes of decreasing grit, then with compound, and it is the longest step in the whole process: every part is finished by hand in our workshop.
What it changes for you
- No chrome bath to redo, ever: we guarantee our bumpers for life against corrosion.
- A scratch can be polished out, since the material is the same all the way through. The method is in caring for a stainless steel bumper.
- The same look as new chrome, without the risk of blistering.
- Weight and rigidity comparable to the original part, so the same brackets and the same fitting.
The full comparison with re-chroming, prices included, is in stainless steel or chrome: the honest comparison. All our models are listed by marque in our marques.
