1) Powder coatings require electrostatic spraying and high-temperature curing, unusable on heat-sensitive substrates (rubber, plastic) or parts too large/thick to bake; thick films prevent thin coats, equipment is expensive and energy-hungry, color change is hard and repair impossible. 2) Electrocoat needs an electric current and a conductive part; unfit for mixed-metal or heat-sensitive assemblies, small batches or large equipment, needs strong technical support and costs much more than water-based. 3) High-solid coatings (volume solids >=70%) are still oil-based with lower solvent than ordinary solvent paints but are less eco-friendly than water-based, with higher process demands and cost.


