Which primer type typically requires a longer setup before painting?

Epoxy primer is the type that typically requires a longer setup before painting due to its specific curing process and chemical properties. When using epoxy primers, it is important to ensure that the primer has fully cured and reached the appropriate hardness before applying topcoat paint. This is often a critical step because epoxy primers can provide superior adhesion and corrosion resistance, which helps improve the overall durability of the paint job.

The extended setup time is necessary to allow the chemical reaction within the primer to occur fully, ensuring the best bonding surface for subsequent layers of paint. If you were to paint over the epoxy primer too early, you risk trapping solvents that may lead to defects in the finish, such as lifting or peeling.

While other primer types also have their own setup times, they generally do not require as much time as epoxy primers. Water-based primers typically have faster drying times due to their makeup, while polyurethanes and shellac-based primers may have different curing characteristics but still do not match the longer requirements of epoxy primers.