What electroplating is and why microns matter
Saturday morning, the atelier full in Goiânia. A client picks up one of my chokers, turns it on its side, and asks: "Patrícia, but is this real gold or just painted on top?" I take a breath and say: "It is real gold, deposited atom by atom on the piece by electric current. The process is called electroplating, and the thickness of that layer is what separates a piece that lasts weeks from a piece that lasts years." She paused, looked again. That is when she understood the price. This lesson is so you have that same answer ready on the tip of your tongue.
What is happening inside the tank
Electroplating is not paint. It is not glue. It is not gold spray. It is real chemistry conducted by electricity.
The piece arrives ready from our factory in polished brass. We dip it into a conductive solution — the electrolyte — that holds 18k gold ions in suspension. On one side of the tank, the positive pole (anode). On the other, the piece, which is the negative pole (cathode). I switch on the direct current.
The gold ions travel, pulled by the current, and anchor themselves one by one onto the surface of the piece. It is not a coating. It is deposition. The gold becomes part of the metal. When I say that to a client, she hears it differently.
What a micron really means
The layer that forms is thin. So thin we measure it in microns — one thousandth of a millimeter. For reference: one of your hairs is between fifty and seventy microns. A sheet of common paper is around one hundred.
The factory does not guess that thickness. It is controlled by four variables my team adjusts in every batch:
- Time inside the tank (ten to thirty minutes per layer).
- Temperature of the electrolyte (between forty and sixty degrees Celsius).
- Electric current intensity (measured in amperes per square decimeter).
- Purity of the electrolyte — any impurity becomes a stain or an adhesion failure.
Move any one of these variables and the final thickness changes. That is why Herreira inspects every batch. Without inspection, plating is not plating — it is a lottery.
Why eight to ten microns change everything
Here is the number you need to memorize, because it is the entire Herreira thesis: the popular demi-fine industry works with two or three micron plating. Herreira starts at eight microns and goes up to ten on pieces meant for daily wear. Three to five times thicker.
The relationship between microns and durability is not linear — it is exponential. Each extra micron withstands far more friction, far more contact with sweat, perfume, lotion. Think of it this way: the plating layer is the only shield between the 18k gold and everyday wear. Two microns is a film. Eight microns is a thin armor, but armor. It is the difference between a piece that darkens in four months and a piece your daughter will still wear.
And no — more micron is not always better. Thick plating over a poor base only stretches the problem. The Herreira recipe is honest 18k gold base (75% gold plus 25% well-chosen other metals) plus eight to ten microns of plating on top. Both things together. Plating does not compensate for poor metal.
At the counter
Client: "But Patrícia, the one at the mall is half the price and also says it is 18k gold plated. Why does this one cost more?"
You: "Because 18k gold plating is only half the story. The other half is thickness. The mall piece usually has two microns — Herreira has eight to ten. That means the gold layer deposited on my piece is three to five times thicker than that one. That is why it lasts years on your body, sweating, with perfume, with lotion. The other one lasts months."
Client: "And how do you manage to make that thicker layer?"
You: "Time in the tank, temperature control, pure electrolyte, and inspection batch by batch. Patrícia has been running the factory in Goiânia since August 2008 — that is eighteen years arriving at the same recipe. It is process, not miracle."
That phrase — "process, not miracle" — is what makes the client feel that you know. And once she feels that, the price stops being an obstacle.
Bridge to the next lesson
Now you know what is happening inside the tank and why eight to ten microns defend the Herreira price. In the next lesson we will take that armor and check, on the piece, what it is protecting: the base alloy. Because thick plating over a bad alloy still fails — and that is where many resellers confuse the client. See you there.