🎨 Manual Spray Gun Paint Mixing Masterclass (QLQ System)
Application: Rack Spraying (Hand Gun).
Target Viscosity (Ford Cup #4): 16 – 18 Seconds (Gloss/Matte); 20 – 22 Seconds (Rubber).
Environment: 25°C, 60% Humidity.
Phase I: The "Golden Formulas" (Production Recipes)
Note: All ratios are by WEIGHT (Grams), not volume. Scales are more accurate than cups.
Formula A: 2K Polyurethane (PU) Enamel (High Gloss/Matte)
The workhorse for zipper pulls and buckles. Hard, durable, chemical resistant.
| Component | Function | Mixing Ratio (Weight) | Sourcing |
| 1. Paint Base (Resin) | Color & Body | 100 g | [QLQ Product] |
| 2. Curing Agent (Hardener) | Cross-linking | 50 g (Standard 2:1) | [Purchase Locally] |
| 3. Thinner (Reducer) | Viscosity & Flow | 40 – 60 g (Adjust to 18 sec) | [Purchase Locally] |
| 4. Adhesion Promoter | Grip on Zinc | 2 – 3 g | [QLQ Product] |
| 5. Anti-Sagging Agent | Prevents Runs | 1 – 2 g | [QLQ Product] |
Pot Life: 4 Hours.
Flash-off Time: 10 mins before oven.
Formula B: Soft Touch / Rubber Paint (Luxury Finish)
Expensive, distinct "velvet" feel. Requires strict mixing.
| Component | Function | Mixing Ratio (Weight) | Sourcing |
| 1. Rubber Paint Base | Tactile Feel | 100 g | [QLQ Product] |
| 2. Rubber Hardener | Curing | 15 g (Usually 10:1.5) | [QLQ Product] |
| 3. Special Thinner | Slow Evaporation | 30 – 40 g (Adjust to 22 sec) | [Purchase Locally] |
Pot Life: 2 Hours (Very short!).
Note: Rubber paint must be mixed gently. Do not whip air into it.
Formula C: 1K NC Lacquer (Vintage/Antique Finishes)
Used for top-coating Antique Bronze/Copper finishes. Air dries fast.
| Component | Function | Mixing Ratio (Weight) | Sourcing |
| 1. NC Clear Lacquer | Protection | 100 g | [QLQ Product] |
| 2. Thinner (Banana Oil) | Solvent | 100 – 120 g (1:1 Ratio) | [Purchase Locally] |
| 3. Hardener | NONE | 0 g | N/A |
Viscosity: Very thin (12 – 14 seconds).
Phase II: The Step-by-Step Mixing Process (SOP)
Pre-requisite: Clean mixing room, Digital Scale, Ford Cup #4, 300 Mesh Filter.
Step 1: Agitate the Base
Action: Open the [QLQ] Paint Can. Use a mechanical mixer or flat stick.
Why? Pigments settle at the bottom. If you pour without stirring, the color will be wrong and the gloss will fail.
Time: Stir for 3 minutes.
Step 2: Weigh the Resin & Additives
Place an empty cup on the scale. Tare (Zero) it.
Pour 100g of Paint Base.
Add [QLQ] Adhesion Promoter and Anti-Sagging Agent now. Stir well.
Step 3: Add Hardener (The Reaction Starts)
Add the Hardener according to the ratio (e.g., 50g).
Stir immediately. Do not let hardener sit on top of the resin.
Step 4: Reduction (Adding Thinner)
Add Thinner slowly. Do not dump it all in at once.
Stir while pouring.
Checkpoint: Lift the stick. The paint should flow in a continuous "string," not drip-drip-drip.
Step 5: The "Viscosity Check" (Mandatory)
Dip the Ford Cup #4 into the mix.
Lift it and start the stopwatch.
Stop when the stream breaks.
Target: 16-18 seconds.
If > 20s: Add 5% Thinner.
If < 14s: Add 5% Base Resin.
Step 6: Maturation (Induction Time)
Crucial for 2K PU: Let the mix sit for 10-15 minutes before putting it in the gun.
Why? Allows the chemical reaction to stabilize and air bubbles to rise out.
Step 7: Filtration
Pour the mix into the Spray Gun Cup through a 300 Mesh Paper Filter.
Never skip this. A tiny dried skin particle will block your gun nozzle and ruin the spray pattern.
Phase III: Master's Adjustments for Hand Spraying
Scenario 1: Spraying Vertical Parts (Hanging Buckles)
Problem: Paint runs down (Sags) easily.
Adjustment:
Reduce Thinner by 5%.
Increase [QLQ] Anti-Sagging Agent by 1%.
Use a Faster Thinner (evaporates quicker).
Scenario 2: High Temperature Day (> 30°C)
Problem: "Dry Spray" (Sandpaper texture). Paint dries before hitting the zipper.
Adjustment:
Use Slow-Drying Thinner or Retarder Solvent.
Lower the Gun Air Pressure (to reduce turbulence drying).
Scenario 3: "Fisheyes" (Silicone Contamination)
Problem: Small craters appear because someone used silicone oil/spray nearby.
Adjustment:
Add [QLQ] Anti-Fisheye Agent (0.5 – 1%).
Warning: Do not overdose, or it will cause adhesion loss.
Phase IV: Gun Setup for Perfect Atomization
Gun Tip Size: 1.0mm – 1.3mm (For Zipper Pulls).
Air Pressure: 2.0 – 2.5 Bar (30-35 PSI).
Fan Pattern:
Open "Fan" knob to 70% width. (Too wide wastes paint; too narrow causes runs).
Fluid Flow:
Turn "Fluid" knob out 2.5 turns.
🌟 Featured Album: The "Mixology Master" Series
Description for the Blog/Guide Album:
🧪 The "Mixology Master" Album: Perfect Paint Recipes for Hand Spraying
The spray gun is just a tool; the Mixture is the magic. In this album, we decode the chemistry of the perfect batch.
What you will learn:
⏳ The "Induction" Secret: Why waiting 15 minutes after mixing prevents "Pinholes" in your PU Enamel.
💧 Thinner Logic: How to choose between "Fast, Medium, and Slow" thinner based on your workshop temperature to stop Dry Spray.
🛑 Stop the Sag: The exact ratio of [QLQ Anti-Sagging Agent] to use when spraying complex, vertical belt buckles.
⚖️ Weight vs. Volume: Why measuring Hardener by volume is costing you money and quality (and why the Scale is King).