Plating Tank Chemical Formular

📖 Tank Make-up Manual: Rack Plating (Zinc Alloy)

Phase I: Pre-treatment Tanks (The "Adhesion" Zone)

1. Hot Soak Degreasing (Chemical Cleaning)

• Tank Material: 304 Stainless Steel (with Ultrasonic).

• Make-up for 1000L:

  • [QLQ Product] Zinc Liquid Dewaxing Agent: 50 – 80 Liters.

  • Pure Water: Balance.

• Operating Parameters:

  • Temp: 70°C – 80°C.

  • Time: 5 – 10 mins.

• Master’s Note: Do not just add water. Add the chemical when the tank is 50% full, then fill up. Heat helps dissolve the surfactants.

2. Cathodic Electrolytic Degreasing (Electro-Clean)

• Tank Material: Mild Steel or PP with SS Anodes.

• Make-up for 1000L:

  • [QLQ Product] Zinc Electro-cleaning Salt: 50 kg (50 g/L).

  • Optional: [Purchase Locally] Potassium Hydroxide: 10 kg (Only if pH < 12).

• Operating Parameters:

  • Temp: 50°C – 60°C.

  • Voltage: 4 – 6 V.

  • Polarity: Workpiece = Negative (-).

• ⚠️ Danger: NEVER use the same electro-cleaner used for Steel parts. High caustic soda will dissolve the Zinc zipper pulls instantly.

3. Acid Activation (Neutralization)

• Tank Material: PP / PVC.

• Make-up for 1000L:

  • [QLQ Product] Zinc Activation Salt (Fluoride-based): 20 kg (20 g/L).

  • [Purchase Locally] Sulfuric Acid: 5 Liters (0.5% vol).

• Operating Parameters:

  • Temp: Room Temp.

  • Time: 5 – 15 seconds.

• ⚠️ Danger: NO Hydrochloric Acid (HCl). HCl causes severe Hydrogen Embrittlement in the stainless steel springs.

Phase II: Base Plating (Copper & Nickel)

4. Cyanide Copper Strike (Alkaline Copper)

• Tank Material: Steel or PP (Heating required).

• Make-up for 1000L:

  • [Purchase Locally] Copper Cyanide (CuCN): 45 kg.

  • [Purchase Locally] Sodium Cyanide (NaCN): 65 kg.

  • [Purchase Locally] Rochelle Salt: 45 kg.

  • [Purchase Locally] Sodium Hydroxide: 5 kg (to adjust pH to 12.5).

  • Optional: [QLQ Product] Copper Anode Activator: 2 Liters.

• Process:

  1. Dissolve NaCN in warm water (50°C) first. Toxic Gas Risk!

  2. Add CuCN slowly into the NaCN solution (it will turn clear).

  3. Add Rochelle Salt.

  4. Check Free Cyanide: Maintain at 15 – 18 g/L.

• Master’s Note: If Free Cyanide is too low, the anodes will turn "black" (passivate). If too high, the plating will blister.

5. Acid Copper (High Leveling)

• Tank Material: PP (Air Agitation + Cooling required).

• Make-up for 1000L:

  • [Purchase Locally] Copper Sulfate (CuSO₄·5H₂O): 200 kg.

  • [Purchase Locally] Sulfuric Acid (H₂SO₄): 60 kg (approx 33 Liters).

  • [Purchase Locally] Hydrochloric Acid: ~100 ml (Target 60-80 ppm Chloride).

  • [QLQ Product] Mu (Make-up Agent): 5 – 8 Liters.

  • [QLQ Product] A (Leveler): 0.5 Liters.

  • [QLQ Product] B (Brightener): 0.5 Liters.

• Process:

  1. Dissolve Copper Sulfate in hot water.

  2. Add Sulfuric Acid slowly (Exothermic reaction - generates heat!).

  3. Treat with [QLQ] Carbon Powder (2 kg) and filter before adding brighteners.

  4. Add Chloride and Additives last.

• ⚠️ Danger: Chloride control is critical. Too much Cl⁻ = Dull plating. Too little Cl⁻ = Burned/Rough plating.

6. Bright Nickel (Watts Nickel)

• Tank Material: PP (Continuous Filtration).

• Make-up for 1000L:

  • [Purchase Locally] Nickel Sulfate: 280 kg.

  • [Purchase Locally] Nickel Chloride: 50 kg.

  • [Purchase Locally] Boric Acid: 45 kg.

  • [QLQ Product] Nickel Softener (Carrier): 10 Liters (High dose for flexibility).

  • [QLQ Product] Nickel Brightener (Main): 0.5 Liters.

  • [QLQ Product] Wetting Agent (Anti-Pit): 1 Liter.

• Process:

  1. Dissolve Nickel salts in hot water (70°C).

  2. Dissolve Boric Acid separately in boiling water (it is hard to dissolve).

  3. Adjust pH to 4.2 using Sulfuric Acid or Nickel Carbonate.

  4. Dummy plate for 4 hours before production.

Phase III: Color Finishes (The QLQ Specialties)

7. Imitation Gold (Brass Alloy)

• Make-up for 1000L:

  • [QLQ Product] Imitation Gold Salt: 120 kg (120 g/L).

  • [Purchase Locally] Potassium Cyanide: 10 kg (Only if specified by formulation).

  • [Purchase Locally] Ammonium Hydroxide: Small amount for color adjustment.

• Operating Parameters:

  • Temp: 30°C – 40°C.

  • pH: 9.5 – 10.5.

  • Anodes: 70/30 Brass Plates or Stainless Steel.

• Master’s Note: Color is controlled by Current and Temp.

  • Too Red? $\rightarrow$ Increase Current / Lower Temp.

  • Too Yellow/White? $\rightarrow$ Decrease Current / Raise Temp.

8. Gunmetal (Tin-Nickel / Tin-Cobalt)

• Make-up for 1000L:

  • [QLQ Product] Gunmetal Make-up Salt: 300 kg.

  • [QLQ Product] Gunmetal Additive A & B: As per manual.

  • [Purchase Locally] Hydrochloric Acid: To adjust pH to 2.0.

• Operating Parameters:

  • Temp: 60°C – 65°C.

  • Anodes: Carbon Graphite or Nickel (Inert).

• Master’s Note: This bath is very sensitive to metallic impurities (Copper/Zinc). Retrieve fallen parts immediately!

9. Rose Gold

• Make-up for 1000L:

  • [QLQ Product] Rose Gold Premixed Solution: 1000 Liters (Ready to use).

  • Self-mixing is difficult and results in unstable color.

• Operating Parameters:

  • Temp: 45°C $\pm$ 1°C.

10. Antique Bronze (Oxidizing)

• Make-up for 1000L:

  • [QLQ Product] Antique Blackener: 100 Liters (10% concentration).

  • Pure Water: 900 Liters.

Phase IV: Post-Treatment

11. Electrolytic Passivation

• Make-up for 1000L:

  • [QLQ Product] Electrolytic Passivation Salt: 50 kg.

• Parameters: Room Temp, 3-5 Volts, 30 seconds.

12. Rack Lacquer (Water-based)

• Make-up:

  • [QLQ Product] Clear Acrylic Dip Lacquer: Use pure (100%) or dilute 1:1 with pure water depending on viscosity.

🌟 Master's "Golden Rules" for Tank Maintenance

1. Dissolving Sequence (Crucial):

   • Never dump powder directly into the main tank. It will settle at the bottom and create a solid "rock."

   • Rule: Dissolve in a separate bucket with hot water, then filter it into the main tank.

2. The "Dummying" Ritual (New Tank):

   • A newly mixed Nickel or Acid Copper tank is "raw" and harsh.

   • Action: You MUST perform "Dummy Plating" (Low current electrolysis at 0.1 A/dm²) for 4-8 hours to remove trace impurities from the raw chemicals before putting in the first real product.

3. Water Quality:

   • Do not use tap water to make up these tanks. Tap water contains Chlorine and Calcium that ruin Acid Copper and Passivation. Use RO Pure Water.

4. Live Entry :

   • For the Cyanide Copper tank: The rectifier must be ON (preset to ~3V) before the Cage Rack enters the liquid.

   • Why? If the zinc parts touch the liquid without current, the copper will deposit loosely (immersion). The plating will peel off during the "Bend Test."

5. Softener Overdose for Springs:

   • For Zipper Pulls with springs: Maintain the [QLQ] Nickel Softener concentration at 120% of the standard level. This ensures the nickel layer is ductile enough to flex without snapping the brittle spring underneath.