Professional Zinc Alloy Surface Finishing Solutions

Special Color Plating

Barrel Plating — Antique Copper, Antique Silver, Black Patina & Custom Colors

Special-effect finishes for barrel: antique bronze, antique silver, black patina, colored e-coat overlay. 8 special colors + Pantone custom. ΔE ≤ 1.0 control.

特殊色样品展示仿古铜/古银/黑古��/彩色电泳等特殊色样品拼图，8种特殊色展示，21:9横幅

Why Barrel Special Colors

Antique and special-effect finishes create distinctive vintage, modern and custom looks — made cost-effective through barrel mass processing

Antique Finishes

Oxidation + wipe + seal process

Black Antique Bronze

Deep aged look, vintage style

Colored E-Coat

Clear color overlay on plated base

8 Colors + Pantone

8 standard + custom ΔE ≤ 1.0

Barrel vs Rack — Special Colors Comparison

How special-effect finishes differ between barrel and rack processes

Factor	Barrel Plating	Rack Plating
Antique finish consistency	Good — barrel tumbling gives uniform oxidation	Excellent — individual control
E-coat color overlay	Good for simple shapes	Excellent for complex shapes
Part-to-part variation	Slightly higher (ΔE ≤ 1.5)	Lower (ΔE ≤ 1.0)
Throughput	5,000-30,000 pcs/batch	200-2,000 pcs/batch
Cost per special-color part	Lower (mass antique processing)	Higher (individual handling)
Color depth/patina control	Barrel rotation time controls patina	Manual application controls patina

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Barrel Special Colors — Process Steps

8 standard finishes plus Pantone custom colors — each with controlled oxidation and sealing

1Base Layer (Cu, Ni or Brass)

Most antique finishes start with a copper, nickel or brass base layer. The base metal determines the final antique color tone.

Key Parameters

Antique copper base: Cu or acid copper

Antique silver base: Bright Ni or Ag

Antique bronze base: Cu-Sn (bronze) alloy

2Oxidation / Patina Formation

Controlled oxidation with chemical patina solutions. Parts tumble in barrel with patina solution for 3-15 minutes. Barrel rotation ensures uniform oxidation.

Key Parameters

Patina type: Sulfide / selenide / permanganate based

Time: 3-15 min

Barrel rotation: 6-10 rpm

Temperature: 30-60 °C depending on patina

3Highlight Wiping (Barrel-Specific)

In barrel, highlights are created by controlled tumbling with abrasive media — removes patina from raised surfaces, leaving depressions dark. This is the 'barrel antique' effect.

Key Parameters

Wiping method: Barrel tumble with fine media 5-10 min

Target effect: High points bright, recesses dark

Media type: Fine walnut / corn cob or soft plastic

Before

After

4Sealing & Protection

Antique finishes are fragile without sealant. Water-clear lacquer or e-coat protects the patina from abrasion and color change from handling oils.

Key Parameters

Sealer type: Clear lacquer or e-coat

Thickness: 10-20 μm (e-coat)

Cure: Lacquer: air dry; E-coat: 160-180 °C

5Colored E-Coat Overlay

For custom colors: plate a neutral base, then apply colored e-coat (RAL, Pantone or custom). The e-coat provides uniform color and high durability.

Key Parameters

E-coat color: RAL / Pantone / custom

Thickness: 15-25 μm

Cure: 160-180 °C, 20-30 min

Color control: ΔE ≤ 1.0 vs target

6Color QC & Tolerance

Spectrophotometer check against master swatch. Antique finishes have inherent variation — we control it by limiting batch size and using calibrated patina solution.

Key Parameters

Tolerance (standard): ΔE ≤ 1.5 for antique finishes

Tolerance (e-coat): ΔE ≤ 1.0

Batch size limit: < 20,000 pcs per batch

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Available Special Colors

8 standard antique and custom colors we run in barrel

Color Name	Base Metal	Patina System	Finish	Best Use
Antique Copper	Copper	Sulfide oxidation	Warm aged copper	Furniture hardware, retro designs
Antique Silver	Nickel	Sulfide + fine wipe	Aged silver look	Costume jewelry, decorative trim
Antique Bronze	Cu-Sn (bronze)	Permanganate patina	Deep brown-bronze	Door handles, vintage hardware
Black Antique Copper	Copper	Heavy sulfide + deep patina	Black-brown aged copper	Tactical, industrial design
Aged Brass	Brass or Cu + Ni	Sulfide + selective wipe	Worn brass effect	Furniture, lighting fixtures
Pewter	Ni-Sn alloy	Matte finish + fine oxide	Soft grey pewter	Modern minimalist hardware
Oil-Rubbed Bronze	Cu + dark oxide	Oil-based patina + seal	Dark, rubbed bronze	Premium door hardware
Oxidized Silver	Silver + sulfide	Controlled tarnish	Toned silver	Jewelry, vintage accessories

📌 Special Colors Cheat Sheet

Antique toleranceΔE ≤ 1.5

E-coat toleranceΔE ≤ 1.0

Patina time3-15 min

Barrel rotation (patina)6-10 rpm

Standard special colors8

Pantone customAvailable (ΔE ≤ 1.0)

Sealer (antique)Lacquer or e-coat

Batch size limit< 20,000 pcs

⚠ Antique finishes have inherent batch-to-batch variationUnlike precise alloy colors (gold, gun metal), antique finishes are chemically induced patinas that vary with: patina bath age, temperature, oxidation time, and barrel rotation speed. Even within a single batch, parts at the top vs bottom of the barrel can differ by ΔE 1-2. We control this by: (1) limiting batch size to 20,000 pcs, (2) pre-aging patina solution, (3) visual sorting under D65 light. Accept 5-10% shade variation as inherent to the antique look.

FAQ

Can I get a consistent antique finish in barrel?

Antique finishes are inherently variable — that's part of their charm. Barrel antique finishes will never be as uniform as rack, but they have a more natural 'aged' variation that many customers prefer. For tight-tolerance antique, use rack. For cost-effective, naturally varying antique, barrel is perfect.

How long does the antique patina last?

Unsealed antique finishes darken over months as the patina continues to react. Sealed (lacquer or e-coat): 2-5 years indoors. Outdoor antique finishes need e-coat protection. We always recommend sealing antique finishes for any product that will be handled.

What's the MOQ for custom Pantone e-coat colors?

1000 pcs for standard RAL colors (stock tint). 5000 pcs for custom Pantone match (requires custom tint formulation, 2-3 weeks development, $200-500 tinting fee).

Can you match a physical sample (not Pantone)?

Yes — send 3-5 sample parts. We spectrophotometer the sample, formulate the patina or e-coat, plate a test batch, and adjust before production. Sample matching adds 5-7 days to the timeline.

Do colored e-coat overlays change the base metal feel?

E-coat adds a resin layer 15-25 μm thick. This slightly softens the 'metallic' feel and adds a glossy sheen unless a matte e-coat is specified. For true metallic feel with color, choose an alloy color instead of e-coat overlay.

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

Special 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