Common Issues & Solutions for Uneven Color in Powder Coating

1. Color Variation Between Batches

Causes

• Unstable raw material quality

• Inaccurate formula weighing

• Poor pigment dispersion during production

• Inconsistent particle size distribution

Solutions

• Use stable, high-quality powder coatings from TYOPSUN with strict batch control

• Standardize and lock production formulas

• Ensure complete dispersion during extrusion

• Use sieved powder with consistent particle size

2. Uneven Color on a Single Workpiece (Light/Dark Spots)

Causes

• Uneven coating thickness

• Improper spray gun distance, angle, or speed

• Unstable electrostatic voltage

• Poor powder fluidization

Solutions

• Adjust spray gun distance to 15–25 cm

• Keep electrostatic voltage at 60–90 kV

• Improve fluidization in the powder hopper

• Ensure uniform spraying speed and path

3. Color Difference Caused by Curing Problems

Causes

• Uneven oven temperature (hot/cold spots)

• Under-curing or over-curing

• Inconsistent conveyor speed

Solutions

• Calibrate oven temperature regularly with an infrared thermometer

• Follow standard curing: 180–200°C for 10–15 minutes

• Keep conveyor speed stable

• Avoid overloading the oven

4. Mottled, Cloudy, or Streaky Color

Causes

• Powder contamination from previous colors

• Residual powder in guns, hoses, or recovery systems

• Moisture in powder or air supply

Solutions

• Thoroughly clean equipment when changing colors

• Use dedicated hoppers or liners for different colors

• Keep powder dry and sieve before use

• Drain moisture from air compressors daily

5. Color Fading or Discoloration After Curing

Causes

• Poor weather resistance of powder

• Overheating during curing

• Unsuitable resin system

Solutions

• Choose TYOPSUN weather-resistant & heat-stable powders

• Strictly control curing temperature and time

• Select the right powder type for your application

6. Uneven Color Due to Poor Pre-Treatment

Causes

• Oil, dust, or rust on the workpiece

• Uneven phosphating or cleaning

Solutions

• Complete degreasing, rinsing, and phosphating

• Ensure the surface is clean and dry before spraying

• Fix surface defects before coating

How TYOPSUN Helps You Solve Uneven Color

• High-stability powder coatings with uniform dispersion

• Strict batch-to-batch color consistency

• Professional technical guidance for spraying, curing, and maintenance

• On-site troubleshooting support