Shenzhen Alu Rapid Prototype Precision Co., Ltd.

Brightening die-cast zinc (often called "zamAK" or zinc alloy) is very doable, and you can get it anywhere from a soft satin look to a mirror-like chrome finish. Here are the most common and effective methods, from simplest to most advanced:

1. Quick & Easy Mechanical Brightening (no chemicals)

a.Clean a.thoroughly first (dish soap + hot water, then rinse and dry).

b.Polish with a soft cotton wheel + green (chromium oxide) or white (aluminum oxide) polishing compound, or even Mother's Mag Polish / Autosol / Flitz on a microfiber cloth.

c.For higher shine: progress to red (rouge) compound or blue compound for final mirror.

d.Many people stop here and clear-coat it afterward.

2. Chemical Brightening / "White Zinc" Look (the classic bright dip)

a.Mix: 1 part concentrated sulfuric acid + 1 part concentrated nitric acid + 8–10 parts water (add acids to water, never water to acid).

b.Immerse the clean part for 5–30 seconds (watch closely – it etches fast).

c.Rinse immediately and thoroughly in running water.

d.he surface will now be very bright and matte-white.

e.Optional: dip in a weak (2–5%) chromate conversion coating (yellow, clear, or olive) for corrosion protection, or just clear-coat it.

3. Ultra-Mirror Finish (for show-quality parts)

a.Start with mechanical polishing to 800–1200 grit (or even diamond paste/lapping).

b.Then do the acid bright dip above – it removes the last micro-scratches and gives an almost chrome-like look.

c.Immediately clear-coat or electroplate (nickel → chrome) if you want permanent shine.

4. Tumbling / Vibratory Finishing (for many small parts)

a.Use ceramic or plastic media + a burnishing compound containing a little citric or oxalic acid.

b.Gives a uniform bright satin finish in a few hours.

Important Tips

a.Zinc is soft – don’t over-polish or you’ll round sharp edges.

b.Always degrease perfectly before any chemical step (trichlorethylene, acetone, or hot alkaline cleaner).

c.Freshly brightened zinc tarnishes quickly in air – clear coat (2K urethane, powder coat, or even spray-can clear lacquer) within hours if you want it to stay bright.