What factors can lead to sagging and running of spray paint?

Inadequate surface preparation can lead to sagging and running of spray paint due to several key reasons. Firstly, a poorly prepared surface may have contaminants such as dirt, grease, or old paint that can affect the adhesion of the new layer. When the paint does not adhere properly, it can form uneven layers, which are prone to running or sagging as the paint dries.

Furthermore, if the surface is not properly smoothed or primed, it can create pockets where excess paint can accumulate, leading to drips and runs. A well-prepared surface ensures that the paint has a proper foundation to adhere to, reducing the likelihood of sagging and allowing for a uniform application.

While other factors, such as poor air quality, high humidity, and using the wrong type of paint can negatively affect the quality of a paint job, inadequate surface preparation directly contributes to the structural integrity of the paint layer, making it a primary factor in preventing sagging and running.