What is the purpose of primer?

• A. To promote adhesion and protect the surface
• B. To seal in paint color
• C. To increase surface roughness
• D. To accelerate rust

Answer: (A)

Primer prepares the surface for a durable paint finish by promoting adhesion and protecting the substrate. It bonds to bare metal or repaired areas, giving the subsequent coats something to grip onto, and it acts as a moisture and chemical barrier to reduce corrosion. It also helps smooth out tiny imperfections so the color coat applies evenly. It isn’t primarily about sealing in the paint color (that’s the job of sealers or the topcoat), it isn’t mainly used to create more surface roughness (that comes from sanding or texture steps), and it doesn’t speed up rust—primers in automotive refinishing are chosen to inhibit corrosion and extend coating life.