Brass: anatomy of the most-used base
Pick up a Herreira piece. Before the 18k gold you see, before the shine that wins the client over, there is a metal body giving it shape, weight and structure. In most of our pieces, that body is brass. And understanding brass is understanding why your piece has the right weight, fits properly and takes the plating the way it does.
The previous module closed with the five real causes of plating peeling. At least two of those causes start here, at the base. So it is worth eight minutes to look inside the piece.
What brass actually is
Brass is an alloy of copper and zinc. The proportion varies: for demi-fine, the Brazilian industry typically works around two-thirds copper and one-third zinc, adjusted by piece type (thin chains need more malleability, rings need more rigidity).
Why does brass dominate the market? Three practical reasons:
- It receives plating faithfully. Once well-polished, the brass surface accepts electrodeposition uniformly. The 18k gold bonds as it should.
- It has the weight of jewelry. Brass is denser than zamac (a cheap alloy used in costume jewelry). When a client holds a plated brass piece, the weight already communicates quality before she reads any tag.
- It is moldable and durable. It allows casting, stamping, drawn chains, soldering. Brass takes whatever the design demands without cracking.
The side of brass nobody tells you about
Brass contains copper. Copper oxidizes. In contact with humid air, sweat, perfume, the copper in the base reacts and forms a greenish layer — that famous patina. While the 18k plating is intact, the client sees nothing because the gold protects it. But the day the plating wears off at some point, what shows up underneath is the brass copper, not the gold.
That is why module 1 lesson 4 insists so much on taking the piece off before the shower, the sea and bed. It is not a manufacturer's quirk. It is chemistry.
Quality brass vs. market brass
Not all brass is equal. Poorly cast brass has porosity — microscopic holes where plating does not bond properly and that turn into peeling points later. Brass with excess impurities (lead, leftovers of other metals) reacts badly to plating and sometimes irritates sensitive skin.
At the factory, I check every raw material batch before sending it to the plating line. Clean brass, careful polishing, well-prepared base — that is how the three-microns-or-more plating Herreira applies stays firm for years.
When brass is not enough
For most clients, Herreira brass is more than enough. But there are two scenarios where it does not solve the problem:
- Skin that reacts to copper or zinc. It is rare but it happens. For those clients, the next lesson covers the hypoallergenic alloy.
- Pieces for water or extreme sports use. Here even the thickest plating does not hold up — and the brass, once exposed, oxidizes fast. The solution is not changing the base, it is changing usage behavior.
The pocket phrase
"The base of most of our pieces is brass, the same alloy used in professional demi-fine. That is why the piece has weight, takes the plating firmly and lasts years with proper care."
What to practice this week
Take three pieces from your kit and feel the weight of each one in your hand. Compare them to a common costume piece, the kind you find at a mall stand. The density difference is real brass against zamac. This sensitivity exercise is what will let you, a month from now, identify a good piece just by holding it — and your client will feel that confidence in your voice.