CraftApril 22, 20265 min read

Inside the coating line: how glass becomes a mirror

Silvering, copper, two coats of protective paint — a walk down the line where float glass turns reflective.

On the Floor

A mirror is one of the oldest manufactured objects, and the process has changed less than you would think. Float glass arrives clean and clear. By the end of our coating line, ninety metres later, it reflects more than ninety-five percent of the light that hits it. What happens in between is chemistry, timing, and a great deal of rinsing.

Sensitise, silver, protect

First the glass is sensitised so silver will bond to it. Then a silver nitrate solution is sprayed across the surface and reduced in place — the reaction that turns transparent glass into a mirror happens in seconds. A layer of copper goes down next to protect the silver from migration, followed by two coats of paint that shield the whole stack from moisture. In a steam-filled bathroom, those last coats are what separate a mirror that lasts twenty years from one that blackens at the edges in two.

The reaction that turns transparent glass into a mirror happens in seconds. Protecting it well takes the rest of the line.
On the Floor

We run the line under our own roof for one reason: control. Every variable that decides a mirror’s lifespan — solution concentration, rinse purity, paint thickness — is ours to hold steady. Outsource the coating and you outsource the warranty along with it.