This is where many export orders go wrong. A sample looks perfect in the showroom, but after two years in a humid bathroom it chalks, spots, or rusts at the joints. In this post we lay out the finish standards Zenova writes into every export PO — including the honest reality of what local anodizing houses actually run.
1. The reality on the anodizing line
Here is what we tell every buyer who walks through our factory: there is no single "one size fits all" film thickness in Zhongshan. The actual oxide thickness depends entirely on the finish — and there is a deliberate trade-off between brightness and corrosion resistance.
Bright silver / polished finish: ≈ 2 µm (≈ 0.08 mil)
For mirror-bright or polished silver profiles, the oxide film is intentionally kept very thin — around 2 µm. Why? A thick anodic layer scatters light and turns a bright silver finish into a milky, hazy surface. To preserve that mirror reflection, the film stays thin. This is the standard practice for high-gloss chrome, mirror silver, and polished champagne finishes.
Brushed / satin finishes: 6 – 8 µm (≈ 0.24 – 0.31 mil)
For brushed, matte, or colored finishes (brushed silver, brushed gold, bronze, etc. — not every finish is a stock option), the surface is already textured, so there is no need to chase mirror reflection. The film can be built up to 6 – 8 µm, which gives meaningfully better corrosion resistance without sacrificing appearance.
What this means for you:
- If your PO says only "anodized aluminum" with no finish and no thickness clause, expect a generic run — and ask the supplier explicitly which family your finish falls into.
- Bright silver at ~2 µm is a brightness decision, not a quality shortcut. If you need a brighter chrome, a 2 µm film is the correct choice.
- If corrosion resistance is the priority (coastal, hospitality, high-humidity projects), specify brushed / matte finishes at 6 – 8 µm.
- At Zenova, we list both options clearly on every drawing: bright silver at the agreed thin spec, or brushed finish at 6 – 8 µm.
2. Powder coating
For black, or custom RAL frames:
- Coating thickness: 40 – 120 µm (≈ 1.6 – 4.7 mil) (typical 60 – 80 µm ≈ 2.4 – 3.1 mil)
- Cross-hatch adhesion (ASTM D3359 / ISO 2409): 0 – 1 grade, no flaking
- NSS: ask for ≥ 480 h NSS for export
Bottom line for your next PO
- Ask which finish family your order falls into: bright silver (~2 µm, for mirror look) or brushed (6 – 8 µm, for corrosion resistance).
- For bright silver, accept ~2 µm as the norm — do not demand 15 µm (≈ 0.6 mil) on a mirror finish; you will lose the brightness you paid for.
- For coastal / hospitality projects, specify brushed / matte finish at 6 – 8 µm.
— The Zenova Engineering Team, Zhongshan, China
