GUIDE · 7 MIN READ

Why a stainless railing darkens by the sea — and how to prevent it.

If you have seen a stainless railing on the coast covered in orange spots, the problem was almost certainly not “bad stainless” — it was the wrong grade, the wrong tools, or a spot the rain never rinses. This is everything we explain to clients about salt air before they sign a quote.

304 VS 316LTHE 5 KM RULEBROWN STAINSSHELTERED SIDESBURAMAINTENANCE

Salt air is not “a little salt in the breeze”.

When wind breaks up waves, fine droplets of seawater stay in the air and travel inland. The water evaporates and chloride salt settles on every surface — the car, the window, the railing. On metal that is not dust you can shake off: the salt draws moisture out of the air and forms a thin film of salt water that stays active for days.

Chlorides are the one thing that seriously bothers stainless steel. They break through the passive chromium layer that protects it, locally, and start pitting corrosion. That is why material by the sea is not chosen by appearance but by how much chloride it tolerates.

Brown stains are usually not your railing rusting.

Nine out of ten “rusted” railings we inspect have healthy stainless underneath the stain. What is rusting are particles of ordinary steel that arrived from elsewhere: dust from a grinder that had been cutting rebar, sparks from a building site, a wire brush, swarf picked up in transport. Those particles rust within days and leave a brown trace on the stainless.

The fix is in the workshop, not in a bottle: tools and discs that never touch carbon steel, separate benches for stainless, and passivation after welding. After that the surface renews itself in open air.

A test any owner can do: if the stain wipes off with a cloth and a little Autosol and the stainless stays bright — it was a foreign particle, not your railing.

304 and 316L: the difference is 2 % molybdenum.

Both are stainless, and on day one both look identical. The difference shows up through the third, fourth and fifth winter — which is why we do not economise on grade near the sea.

	AISI 304	AISI 316L
Alloy	18 % Cr, 8 % Ni	16 % Cr, 10 % Ni, 2 % Mo
Chloride resistance	vulnerable	considerably higher
Where it is used	indoors, > 5 km from the sea	the coast, boats, pools
Difference in fence price	the baseline	dearer — the exact difference is in the quote

The “L” in 316L means lower carbon — a less sensitive zone around the weld.

The five-kilometre rule.

How much salt reaches you depends on the distance from the sea, but also on whether the path is open. The bura carries aerosol far inland over bare karst; a dense pine wood stops it within a few hundred metres. This is the framework we recommend a grade by.

0 – 100 m

316L, no exceptions.

Front row, waterfront, a terrace above the waves. Salt arrives every day, not only with the bura.

100 m – 1 km

316L or powder-coated aluminium.

304 survives here, but not without stains — we do not recommend it.

1 – 5 km

Aluminium or 304.

Salt only arrives with a strong bura. Rain does most of the rinsing.

> 5 km

304 is enough.

Paying for 316L makes no sense — better to spend it on the finish and the infill.

Kapljice kiše na inox ogradi — kiša ispire sol koja bi inače ostala na metalu

The sheltered side rusts first. Rain, ironically, helps.

Salt the rain washes off does no damage. Salt that stays does. That is why we find the first stains in places that look “protected”: under a canopy or the balcony above, on the underside of a handrail, in the joints and under a post cap, on the side of the railing facing away from the rain.

CHECK THESE FIRST

The underside of the handrail, the post-to-plate joint, anything under a canopy.

WHAT TO DO

Hose those spots deliberately — the rain does not get there.

The bura does two things at once.

First, it carries salt further inland than any other wind on the Adriatic. Second, it attacks the railing mechanically: gusts, the infill vibrating, sand and small stones grinding across the surface and damaging the passive layer locally. A railing by the sea therefore has to be more than the right material — it has to be structurally quiet: a shorter span between posts, a 2 mm wall instead of 1.5, anchoring into concrete with A4 bolts, and an infill that does not rattle.

Six things that prevent stains.

The right grade from the start.

316L in the front row, bolts and anchor plates included. One carbon-steel bolt ruins the whole railing.

Clean tools.

Discs and brushes that have never touched carbon steel, and a separate bench.

Weld finishing.

Oxide removal and passivation — the weld is the most vulnerable point on the whole railing.

A smooth face.

The finer the polish, the less salt and moisture stay on the surface.

Rinsing with fresh water.

After a bura or a strong jugo — a hose, five minutes, no products at all.

Never chlorine or acids.

Bathroom cleaners, bleach and “rust remover” damage stainless steel permanently.

MAINTENANCE

Looking after a stainless railing by the sea — one page.

The same instruction sheet that goes out with every fence we make. No expensive products and no service visit twice a year — a hose, a mild detergent and five minutes.

AFTER EVERY BURARinse with fresh water, especially the underside of the handrail and any part under a roof.

TWICE A YEARA soft cloth, water and a mild washing-up detergent. Wipe along the grain.

ONCE A YEARAutosol or a stainless-steel paste on anything that has darkened — it brings the shine back and closes the surface.

NEVERWire brushes, steel wool, chlorine, rust removers and acidic detergents.

CALL USIf a stain will not wipe off, or if one appears on a weld — get in touch and we come and look.

Ask for the care sheet ›

Send a photo of your railing — we will tell you what it is.

If you already have stains, a photograph usually shows whether it is a foreign particle, the wrong grade, or the weld. The answer is free and commits you to nothing.

Send a photo of the stains ›