Pre-Paint Preparation Guide

🏅 Surface Prep Masterplan for Badges & Crafts (QLQ System)

Substrates: Zinc Alloy (Die-cast) or Iron/Brass (Stamped).

Goal: A "Tooth-like" surface for paint to grip, without destroying fine details.

Phase I: Vibratory Deburring & Polishing (The "Detail Safe" Method)

For badges, we avoid aggressive Rotary Barrels (which nick edges). We use Vibratory Bowls.

1. Media Selection (The Critical Choice)

• The Problem: Badges have tiny holes (for pins) and deep recesses (logos). Media getting stuck (Lodging) is the #1 nightmare.

• The Solution:

  • For Zinc: Use Plastic/Resin Media (Cones or Pyramids). It cuts gently and doesn't "peen" (close up) the pores.

  • For Iron: Use Ceramic Media (Angle Cut Triangles).

• Anti-Lodging Rule: The media size must be either 70% smaller than the smallest hole OR 150% larger than the largest hole. Never the same size!

2. The Process Steps

• Step A: Deburring (Removing Flash):

  • Media: Green/Blue Plastic Media (Medium cut).

  • Chemical: [QLQ Product] Deburring Compound.

  • Time: 2–3 Hours.

  • Note: Use a lower vibration amplitude to prevent badges from hitting each other (nicking).

• Step B: Surface Smoothing (Leveling):

  • Media: Porcelain balls or High-Density Plastic.

  • Chemical: [QLQ Product] Bright Polishing Liquid.

  • Time: 1–2 Hours.

  • Goal: Remove the "scratch pattern" from Step A, but do not mirror polish. Paint needs a slight matte texture to stick. Too shiny = Poor adhesion.

3. Common Mechanical Problems & Fixes

• Issue: "Flat-on-Flat" Sticking. Flat badges stick together like wet coins.

  • Fix: Use [QLQ Product] Anti-Sticking Compound. Increase the ratio of Media-to-Parts to 4:1.

• Issue: Rolled Edges. The sharp corners of the logo look rounded/blurry.

  • Fix: Shorten the time. Use smaller, faster-cutting media.

Phase II: Phosphating & Chemical Conversion (The "Invisible Glue")

Note: "Phosphating" is strictly for Steel/Iron. For Zinc Alloy, we use "Chromating" or "Zirconium Silane."

Scenario A: For Iron/Steel Badges (Zinc Phosphate)

• Process: Degrease $\rightarrow$ Rinse $\rightarrow$ Surface Conditioning $\rightarrow$ Phosphating $\rightarrow$ Rinse $\rightarrow$ Dry.

• The Chemical Bath:

  • [QLQ Product] Zinc Phosphate Salt: 50 g/L.

  • [QLQ Product] Accelerator: As needed.

  • Temp: 60°C – 80°C.

  • Time: 5 – 10 mins.

• The Result: A grey, crystalline coating. The paint soaks into these crystals and locks on.

Scenario B: For Zinc Alloy Badges (Chromate / ZAP)

• Process: Degrease $\rightarrow$ Activation (Weak Acid) $\rightarrow$ Conversion Coating $\rightarrow$ Rinse $\rightarrow$ Oven Dry.

• The Chemical Bath:

  • Option 1 (Traditional): Yellow/Clear Chromate (Hexavalent is banned; Trivalent is OK).

  • Option 2 (Advanced QLQ): [QLQ Product] Nano-Ceramic Adhesion Promoter (ZAP).

    • Advantage: Eco-friendly, no heavy metals, creates a nano-scale coating that bonds paint chemically.

    • Temp: Room Temp.

    • Time: 1 – 2 mins.

Phase III: Master's Experience Share (Real World SOP)

1. The "Water Break" Warning

• Observation: Before the badges enter the Phosphating/ZAP tank, lift one up.

• Test: Does water cover the whole badge smoothly?

• Reality: If you see water beading up on the logo, the polishing wax is still there. Phosphating will fail.

• Action: Strengthen the Ultrasonic Degreasing step immediately.

2. The Drying Temperature Trap

• Observation: Drying the parts after Phosphating.

• Rule: Do not bake Iron Phosphate > 140°C.

• Why? High heat breaks down the phosphate crystal water (dehydration), turning the coating into powder. The paint will peel off with the powder.

• SOP: Dry at 100°C – 120°C max. Paint curing comes after painting.

3. Racking Marks (Shadows)

• Issue: Badges are often painted on flat trays. The contact point doesn't get painted.

• Solution: Use "Pin Racks" (Needle points) that hold the badge by the back pin or the screw hole. Never lay a high-end badge flat on a mesh belt if you want 360° coverage.

4. The "Dust" Defect

• Issue: Phosphating leaves a loose "sludge" or white dust on the badge.

• Cause: The solution has too much sediment/sludge.

• Fix: Phosphate tanks need a "Settling Zone" or filtration.

• Quick Fix: A "Passive Rinse" (Hot water + weak sealer) helps wash away loose dust before drying.

Phase IV: Troubleshooting Guide (Q&A)

Description for the Blog/Guide Album:

🏅 The "Badge Perfection" Album: Preparing High-Value Crafts for Paint

A Nameplate is the "Face" of a product. If the paint falls off the logo, the brand looks cheap. This album bridges the gap between Dirty Polishing and Pristine Painting.

What's Inside:

• 🛑 Stop the "Lodging": A definitive chart on selecting the right Media Size vs. Badge Hole Size. Never pick media out of a hole with a needle again!

• ⚗️ Iron vs. Zinc: Why treating Zinc Alloy like Steel is the biggest mistake in phosphating. We explain the [QLQ Nano-ZAP] technology that replaces old-school sludge baths.

• 🔍 The "Crystal Size" Secret: Why big phosphate crystals ruin your gloss paint, and how to get the "Micro-Crystalline" finish for that luxury look.

• 🔥 The Pre-Bake Protocol: How to prevent die-cast zinc from "spitting" gas bubbles into your wet paint during the curing cycle.

👉 Ensure your badges survive the test of time. Read the Craft Preparation Album now!