Grade is the decision
Stainless steel resists corrosion because chromium forms a thin passive oxide layer that re-forms when damaged. What varies between grades is how well that layer holds up against chlorides — which is to say, against salt.
304. The common austenitic grade. Excellent in most environments, and perfectly adequate inland or internally.
316. Contains molybdenum, which substantially improves chloride resistance. This is the grade for coastal and seafront exposure, and in much of Mumbai it should be the default rather than the upgrade.
Specifying 304 where 316 belongs produces exactly the rust staining that stainless is supposed to eliminate — and once it appears on a balustrade or a cable system, it cannot be polished away permanently.
This is why every invisible grill cable and fitting we supply is specified for marine exposure rather than to a general standard.
The three ways stainless ends up rusting
Wrong grade for the exposure. As above. The most common cause.
Carbon steel contamination. If stainless is cut, ground or handled with tools that have been used on carbon steel, particles embed in the surface and rust there. It looks like the stainless has failed; it has not. This is why stainless is fabricated with dedicated tooling.
Mixed fixings. A 316 member bolted with a lower-grade fastener will show rust at every bolt. The fixings are part of the specification, not an afterthought.
Finishes
Brushed / satin. A directional grain, the standard architectural finish. Hides marks well and is easy to match.
Mirror polish. Reflective. Beautiful and unforgiving — every fingerprint and scratch shows.
Bead-blasted. Matt and uniform, with no direction. Good where members meet at angles and a grain direction would be awkward.
Consistency matters more than the choice. A single member finished differently from its neighbours is immediately visible, so a whole assembly is finished together.
Where we use it
Glass railing hardware. Standoffs, clamps, posts and handrails — exposed, handled, and directly in the salt.
Invisible grill cable and fittings. Where grade choice most directly determines service life.
Architectural metalwork. Handrails, entrance features, signage frames, and trim.
Structural members where exposure rules out protected carbon steel and the cost is justified.
For most structural work, steel with proper protection is the economical answer, and aluminium covers the light, corrosion-resistant middle ground. See the full structural fabrication range.