Appearance looks uneven and broken before curing.
Back ionisation occurring. Where voltage is too high, or where the gun nozzle is too close to the part the powder layer reaches a saturation point, beyond which additional coating is deflected off the surface and eventually causing the deposited film to jump off the part, creating craters and star-like patterns in the powder film.
Check the electrical earth and that the grounding points are clean. Decrease the voltage by 10-20 kV. Move gun further away from component.
Uneven light to dark or matt to glossy effect of the coating on the substrate
Spray gun settings:
Test and optimise gun settings
Micropinholing from gassing caused by
Ensure that humidity levels are controlled and that the air line is clean and dry. Check that the substrate has not trapped air or moisture by pre-heating it slightly above the curing temperature of the coating, allowing to cool then powder coating.
Haze like film on the surface, which can be wiped off
By-products of resin manufacture depositing on surface because their energy is too low to sublime off the substrate. Caused by
Ensure metal temperatures reach the recommended curing temperature. Whilst coatings will cure at reduced temperatures when given a longer cure, this may cause severe blooming. Do not leave products to cool in a box oven. Once the curing cycle is complete, open the oven doors and remove the work.
Insufficient air circulation in the oven
Increase air circulation
Contamination on the surface because of incompatible powder coatings from different manufacturers
Use only powder coatings from one manufacturer at the same time in an oven. Contact us.