Professional Zinc Alloy Surface Finishing Solutions

金色电镀

Barrel Gold Plating — 24K, Rose, Champagne, Green & Light Gold

Precious metal barrel plating: 24K, light gold, rose gold, champagne, green gold. Gold salt concentration, free cyanide control, 0.1-0.5 μm decorative thickness. Cost management for small-batch gold salt.

Why Barrel Gold Plating

Gold gives the ultimate luxury finish — barrel processing makes it affordable for mass-produced small hardware

24K Gold

99.9% pure, luxury-grade finish

Color Golds

Light, rose, champagne, green gold

Decorative Thickness

0.1-0.5 μm — affordable luxury

Gold Salt Control

Precise dosing, auto-replenishment

Barrel vs Rack — Gold Plating Comparison

Cost and process differences between barrel and rack gold plating

Parameter	Barrel Plating	Rack Plating
Current density	0.3-1.0 A/dm²	0.5-2.0 A/dm²
Gold salt (as Au)	1-5 g/L AuK(CN)₂	2-8 g/L AuK(CN)₂
Free KCN	10-20 g/L	15-30 g/L
Temperature	50-65 °C	50-70 °C
Barrel rotation	6-10 rpm	N/A
Thickness typical	0.1-0.5 μm	0.5-5 μm
Gold usage efficiency	Lower (drag-out loss in barrel)	Higher (recovery easier)
Cost per part (0.1μm)	Low (batch size spreads cost)	High (per-part handling)

▼

Barrel Gold Plating — Process Steps

Luxury finish for mass-produced small parts

1Gold Bath Make-up

Gold solution based on gold potassium cyanide (AuK(CN)₂). Free cyanide maintains anode dissolution and prevents decomposition. pH and temperature precisely controlled.

Key Parameters

AuK(CN)₂ as Au: 1-5 g/L

Free KCN: 10-20 g/L

pH: 9.5-11.5

Temperature: 50-65 °C

金槽槽液镀金槽液，含金盐 1-5 g/L AuK(CN)₂，游离氰 10-20 g/L，温度 50-65°C

2Barrel Loading & Gold Plating

Load base-plated parts (usually bright nickel) into barrel. Gold flashes in 30-120 seconds. Barrel rotation ensures uniform gold coverage. Low current density to avoid burning.

Key Parameters

Current density: 0.3-1.0 A/dm²

Time: 30-120 s

Barrel rotation: 6-10 rpm

Anode: Platinized titanium or stainless steel

Before

After

3Color Formulation — 5 Gold Tones

Gold tone is adjusted by alloy composition: 24K (pure Au), light gold (Au-Ag), rose gold (Au-Cu), champagne (Au-Ag-Cu), green gold (Au-Ag-Cd or Au-Ag-Ni). Each has a specific bath formulation.

Key Parameters

24K (99.9% Au): Pure Au deposit, warm yellow

Light gold: Au-Ag alloy, pale yellow

Rose gold: Au-Cu alloy, 75-85% Au, pink tone

Champagne: Au-Ag-Cu, soft golden-pink

Green gold: Au-Ag-Ni, greenish tint

7Gold Salt Management (Cost Control)

Gold is expensive — precise control of gold salt in bath and drag-out recovery is critical. Auto-dosing by ampere-hour and drag-out recovery tank minimize gold loss.

Key Parameters

Gold cost: Track per batch (Au consumption = kAh × 0.3-0.8 g/kAh)

Drag-out recovery: Return rinses to bath or recovery tank

Auto-dosing: Peristaltic pump linked to Ah meter

5Anti-Tarnish Treatment

Gold doesn't tarnish, but the base metals in rose gold and green gold alloys can. Anti-tarnish dip (organic inhibitor or Cr³⁺) protects the alloy golds.

Key Parameters

Anti-tarnish method: Organic inhibitor 0.5-2%

Rinse: DI water only

Drying: 60-80 °C, 10-15 min

6Thickness Verification

XRF verification of gold thickness. Decorative gold 0.1-0.5 μm is thin — XRF must be calibrated for thin gold films on nickel.

Key Parameters

Thickness range: 0.1-0.5 μm

Measurement method: XRF (Au on Ni)

Batch sampling: 10 parts / 5000 pcs batch

XRF膜厚检测 XRF 膜厚仪检测金层厚度，0.1-0.5 μm 装饰金层精确测量

▼

Gold Color Comparison Chart

All gold tones available for barrel plating

Gold Type	Alloy	Au%	Appearance	Typical Thickness	Best Use
24K Gold	Pure Au	99.9%	Warm yellow gold	0.3-1.0 μm	Premium jewelry, religious items
Light Gold	Au-Ag	90-95%	Pale, soft gold	0.1-0.3 μm	Cost-sensitive fashion hardware
Rose Gold	Au-Cu	75-85%	Pinkish warm tone	0.1-0.3 μm	Luxury bags, fashion jewelry
Champagne Gold	Au-Ag-Cu	80-90%	Soft golden-pink	0.1-0.3 μm	Watches, premium bags
Green Gold	Au-Ag-Ni	85-95%	Greenish yellow tint	0.1-0.3 μm	Fashion accessories, eyewear

📌 Gold Plating Cheat Sheet

AuK(CN)₂ (as Au)1-5 g/L

Free KCN10-20 g/L

pH range9.5-11.5

Temperature50-65 °C

Barrel current density0.3-1.0 A/dm²

Time (decorative)30-120 s

Thickness (decorative)0.1-0.5 μm

Gold color alloys5 types

💡 Gold cost calculation for barrel platingGold cost per batch = (Total Ah) × (Gold consumption rate, typically 0.3-0.8 g/kAh for 0.1 μm) × (Gold price per gram). For a typical barrel batch of 10,000 small parts at 0.1 μm Au, gold consumption ≈ 0.5-1.0 g. Drag-out recovery can save 20-30% of the gold salt. Use a dedicated drag-out tank after the gold bath and return the concentrated rinse back to the bath.

FAQ

What's the minimum gold thickness for barrel plating?

0.05 μm is technically feasible but risks pinhole coverage. We recommend 0.1 μm minimum for decorative consistency. At 0.05 μm, the base nickel color may show through on edges and corners.

Does barrel gold plate better on nickel or copper?

Both work, but nickel gives a brighter, whiter base that makes gold appear more vibrant. Copper base makes gold appear warmer (more reddish). For rose gold, copper base is preferred. For 24K and light gold, nickel base is standard.

How do I avoid gold thickness variation in barrel?

Three causes: (1) poor current distribution (use anodes on both sides of barrel), (2) insufficient rotation (increase to 8-10 rpm), (3) too many parts in barrel (reduce load to 50-60%). XRF check 10 parts from different barrel positions per batch.

What causes gold 'burning' in barrel?

Same as other metals — too much current for barrel geometry. Gold is especially sensitive because it's expensive (any wasted Au is lost). Keep gold current density at 0.3-1.0 A/dm². Above 1.5 A/dm² in barrel, expect brownish 'burnt' deposits that require stripping and re-plating.

Can you do REACH-compliant gold plating?

Yes — all our gold baths are cyanide-based (there is no practical non-cyanide gold bath for decorative plating). But waste treatment includes cyanide destruction before discharge. Gold itself is REACH compliant. For EU-bound orders, we provide full documentation.

Get a Free Quote Today

Send us your samples or drawings — our engineers reply within 24 hours with pricing and technical advice.

Workshop Planning Data

Golden Color Plating — Data Zinc Alloy Finishing Managers Need

The automatic barrel plating line plates zinc alloy small parts with copper, nickel, tin and color finishes in batches of 50,000+ pieces, delivering uniform thickness and color at the lowest cost per piece.

650 m²Workshop Area

22 peopleTeam Size

260 kWInstalled Power

1.2-2.5M pcs/dayDaily Output (10 h)

Quality Inspection & Control

Check item	Method	Acceptance standard
Coating thickness	X-ray fluorescence / coulometric	Per spec: Cu 3-8 μm, Ni 3-10 μm, Sn 3-6 μm
Adhesion	Bend / peel / thermal shock	No flaking at 150 °C × 30 min
Color match	Colorimeter ΔE / master	ΔE ≤ 1.5 vs approved master
Salt spray	NSS chamber	12-72 h per finish spec
Pitting / roughness	10× inspection	No pitting, nodules or burnt deposits
Thickness uniformity	5 positions / batch	CV ≤ 10% across barrel load

Workshop Layout & Floor Area

Zone	Area
Automatic barrel line (12-16 tanks)	260 m²
Chemical storage / dosing	60 m²
Rectifier room	40 m²
QA lab + X-ray	50 m²
Dryer / centrifuge / sorting	80 m²
Rinse & waste treatment	110 m²
Utility & lockers	50 m²
Total workshop	650 m²

Manpower & Shift Plan

Role	Headcount
Line operators	10
Chemical technicians	3
QC inspectors (incl. X-ray)	3
Wastewater operator	1
Supervisor	1
Maintenance / electrician	2
Logistics & sorting	2
Total (2 shifts × 10 h)	22

Power & Utility Demand

Equipment	Demand
Rectifiers 12 V × 500-2000 A (4 sets)	80 kW
Tank heating + cooling	55 kW
Barrel drive motors (12-16)	24 kW
Pumps / filters / dosing	30 kW
Exhaust + scrubber	22 kW
Dryer + centrifuge	20 kW
Wastewater treatment	18 kW
Lighting & auxiliary	11 kW
Installed total	260 kW
Typical running load	≈ 205 kW

Production Flow Chart

PretreatmentPolish, degrease, activate

Alkaline CopperStrike layer for adhesion

Acid Copper / Nickel / TinBuild thickness + brightness

Color FinishGold, gun, black, antique etc.

Rinse ChainRecovery → counter-flow → DI

Dry & SortCentrifuge, inspect, pack

Daily Capacity — 10-Hour Operating Day

Parameter	Value
Batch cycle	25-45 min
Load per barrel	40-80 kg
Parts per batch	50,000-100,000
Batches per 10 h day	14-20
Daily output	1,200,000-2,500,000 pcs
Monthly output (26 days)	31-65 million pcs

Output Value Estimate

Parameter	Value
Plating fee per piece	USD 0.005-0.015
Daily output value (10 h)	USD 7,000-18,000
Monthly output value	USD 180,000-470,000
Annual output value	USD 2,160,000-5,600,000