A mirror-polished stainless steel bumper asks for almost nothing: water, a soft cloth, and a polish now and then. Here is what we recommend to keep it looking as it did on day one, and what you must never do.
Routine washing
- Clean water and ordinary car shampoo, with a microfibre cloth or a clean sponge with no grit trapped in it: it is the sand that scratches, not the sponge.
- Rinse and dry with a dry microfibre cloth to avoid limescale marks, especially in hard water areas.
- After winter or a trip to the coast, rinse generously: 304 stainless steel resists salt, but a dried salt deposit eventually leaves brown surface marks, easy to remove as long as they are not left for months.
What not to use
- No steel wool or abrasive kitchen scourers: they scratch the mirror finish and can leave iron particles that rust on the surface.
- No bleach or chlorine-based descaler: chlorine is the only real enemy of stainless steel, it causes pitting.
- No pressure washer at close range on overriders with rubber inserts.
- No ‘chrome restorer’ products containing coarse abrasives: they are made for dull chrome, not for a mirror polish.
Bringing back the shine
Two or three times a year, or before a meet, a mild metal polish (of the kind used for household stainless steel or polished aluminium), applied with a microfibre cloth in straight strokes along the length, then wiped off, brings back the original mirror finish. Avoid circular motions, which leave micro-scratches that show in bright sunlight.
A scratch
This is the advantage of stainless steel over chrome: a scratch does not go through any layer, so it can be brought back.
- Light scratch (your fingernail does not catch): metal polish, microfibre cloth, along the length, several passes.
- Deeper scratch (your fingernail catches): fine polishing compound on a cotton mop fitted to a drill at low speed, without pressing, then finishing polish. If you have never polished stainless steel before, try it first on the hidden face of the blade, or send the part to us.
- Knock or distortion: do not try to straighten a polished stainless steel bumper with a hammer, the mirror finish will not recover. Send us photos and we will tell you whether the part can be reworked in the workshop.
Brown or orange spots
A brown spot on 304 stainless steel is almost never the material itself rusting: it is an iron particle from elsewhere (brake disc dust, swarf, steel wool) that has oxidised on the surface. It comes off with polish or with an off-the-shelf stainless steel cleaner. If a spot keeps coming back in the same place, write to us with a photo.
Storage
A bumper that has been taken off should be stored dry, flat or hung up, with the mirror finish protected by a cloth or foam, never in direct contact with another metal. No need for oil or wax: stainless steel does not rust sitting in a workshop.
Why this material behaves as it does is explained in why 304 stainless steel at 2 mm. The comparison with chrome, which cannot be brought back, is in stainless steel or chrome.
