What does "pretreatment" mean in the context of painting?

Pretreatment in the context of painting refers to the steps taken to clean and prepare a substrate before any paint application occurs. This process is critical because it ensures that the surface is free of contaminants such as dust, grease, oils, and old paint residues, which can interfere with the adhesion and final appearance of the paint.

Proper pretreatment can involve various methods such as washing, sanding, or chemical treatments, depending on the type of substrate and the conditions it has been exposed to. For example, metal surfaces often require degreasing and may need to be treated to prevent rust. Additionally, pretreatment can include priming, but only after the surface has been properly cleaned and prepared.

While applying primer directly to the surface is an important part of the painting process, it follows the pretreatment phase and does not encompass the full scope of preparing a substrate. Mixing paint with solvents relates to achieving the right viscosity for application but is a separate consideration. Lastly, final inspection occurs after all preparatory work, ensuring everything is in order before the actual painting begins.