Antique galvanized with rust: how to "recharge" the zinc before it's too late

Hot-dip galvanizing is an excellent protection, but it has a limited lifespan: the zinc is gradually consumed to protect the steel. In an aggressive environment, a galvanized layer can be depleted in 15–25 years. When that happens, the steel starts to rust and the structure loses value and safety.

Signs that the galvanizing is wearing out

• White rust (whitish powder): the zinc is working. It is normal, but indicates wear.
• Dull and dark areas instead of the original shine.
• Red rust spots: the zinc has been depleted there and the steel is already corroding. It is time to act.
• Rust on screws, welds, and edges: they are usually the first points to fail.

Replenish the cathodic protection

The advantage of cold galvanizing is that it can be applied on site, without dismantling or taking anything to a galvanizing plant. GALVANOL is applied directly over the old galvanizing or over a surface treated years ago with GALVANOL itself, and replenishes the zinc in the system.

How to do it

1. Remove loose red rust with a steel wire brush or sandpaper until you reach solid metal.
2. Remove white rust and dirt; wash if there is salt or contamination.
3. Degrease with xylene and let dry.
4. Apply GALVANOL to the damaged areas and then a general coat over the entire structure. Recommended: 2 coats, or 3 in marine or industrial environments.

Why not wait?

As long as there is zinc left, maintenance is quick and cheap: clean and apply. When red rust advances and pits the steel, the repair is much more expensive and sometimes parts have to be replaced. Inspecting galvanized structures once a year and touching up in time multiplies their useful life.

For spot touch-ups, the GALVANOL Spray 500 ml is the most convenient. For complete structures, the 10 kg bucket covers about 20 m² at 2 coats.