Nov 06, 2025
1. Breaking the “Blend Edge” Problem in Automotive Refinishing
In traditional car refinishing, one of the biggest challenges during clear coat application is the visible blend edge when spraying over an un-sanded old paint surface. This often leads to peeling, poor adhesion, or uneven gloss — all of which compromise the finish quality and reduce repair efficiency.
WB-340 Seamless Clear Coat was developed precisely to solve this industry-wide issue. As the second-generation upgraded version, it features an advanced resin system and enhanced adhesion technology that allows new and old paint layers to naturally blend into one flawless surface, achieving a factory-quality finish without visible repair edges.
2. Core Advantages
The strength of WB-340 lies in its ability to merge seamlessly with the existing paint surface — delivering an invisible repair effect both inside and beyond the blend area.
Perfect Integration: Whether blending inside the sanded area or extending slightly beyond, WB-340 creates a smooth, boundary-free transition after polishing.
Texture Matching: By adjusting viscosity, users can accurately reproduce the OEM texture of different vehicle types — • German cars: heavier texture (use as is, no thinner needed) • Japanese cars: finer texture (add thinner as required)
Fast & Easy Application: Quick-drying performance makes it ideal for localized spot repair when used with 1K basecoat systems.
High Transparency & Strong Adhesion: Can be applied directly on the cleaned and polished old surface, ensuring excellent adhesion, high gloss, and superior transparency.
3. Simple Application Steps for a Flawless, Invisible Finish
WB-340 is user-friendly and highly tolerant — perfect for both professional and semi-professional painters.
Step 1: Surface Preparation
Sand the old paint surface with fine sandpaper and remove impurities.
Apply and level putty, then sand smooth after drying.
Mask edges with tape to ensure clean lines and minimal break zones.
Step 2: Primer Application
Apply primer and dry thoroughly. Sand to smooth using P400–P600, then finish with P2000 dry sanding.
Polish surrounding areas for a natural blend transition.
Degrease and remove dust before applying basecoat.
Step 3: Clear Coat Application
Mixing ratio: Clear coat : Hardener : Thinner = 100 : 50 : 0–10 (Recommended hardener: WB-345)
Apply 1.5–2 coats with spray pressure 1–1.5 kgf/cm² and nozzle size 0.4–1.0 mm.
Allow 2–3 minutes flash-off between coats before baking.
Bake at 60 °C for 15 min for polishing, or 60 °C for 60 min for sanding/rework.
Step 4: Polishing & Finishing Use a blending thinner to fine-tune the transition area. Test both:
External blend: spraying beyond the old clear coat area
Internal blend: spraying within the sanded area
After 15 min baking + 10 min cooling, polishing reveals a completely seamless finish — no visible edge, even under reflective light.
4. Safety & Technical Notes
2K PU hardeners are moisture-sensitive — always seal tightly after use.
Ensure the spray system is completely dry to prevent paint defects.
Always wear protective masks and ensure proper ventilation.
Avoid air drying; use infrared or temperature-controlled baking for best results.
As conditions vary, conduct a compatibility test before large-scale application. Technical support is available for specific requirements.
5. Conclusion
Whether for partial spot repair, used car refinishing, or premium body shops, WB-340 Seamless Clear Coat helps painters eliminate concerns about blend edges, drying times, and color mismatch. It allows professionals to focus on restoring a perfect glossy surface — delivering faster, higher-quality automotive refinishing results.
WB-340 — the ultimate solution for efficient, flawless automotive repair.
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