What is the Function of Automotive Intermediate Primer?

[MollyLee]

Automotive intermediate primer serves the following purposes: 1. Filling function: It fills the capillary pores in the steel plate, facilitating the application of surface paint; 2. Supporting the topcoat: It ensures the topcoat can adhere tightly to the vehicle's surface; 3. Providing fullness: The primer contains numerous fillers that enhance the paint's thickness. Automotive primer is the first coating directly applied to the surface-treated metal components, marking the beginning of the entire coating process. It is designed to have excellent adhesion to the substrate, good compatibility with the intermediate or topcoat layers above, and must also possess superior corrosion resistance, rust prevention, oil resistance, chemical resistance, and water resistance.

[McRylee]

When your car gets scratched or scraped on the road, the primer can truly be a lifesaver. Simply put, this layer of paint acts like protective clothing for the metal body, shielding it from annoying moisture and oxygen in the air, preventing rust from forming! I've personally seen scratches without primer—within two months, the entire edge was covered in rust spots. Plus, it's incredibly adhesive, sticking to the metal like double-sided tape, so any topcoat sprayed over it won't peel. Oh, and the primer also fills in fine scratches, smoothing out those tiny marks left from sanding. The most amazing part is how it bonds different materials together, like connecting a plastic bumper to the metal body. Honestly, this stuff is the real MVP of car paint—no matter how beautiful the topcoat is, it all relies on the primer as the foundation!

[MacCamilla]

Body repair professionals all understand that the primer isn't applied for nothing. It acts like super glue between the metal and topcoat - without it, the paint would just flake off. When we restore classic cars, after grinding with metal rust remover, we must immediately spray two coats of primer. Once cured, this hardened film showed remarkable durability in our aluminum hood test - knife marks left only white scratches without actual damage. I remember treating rust holes on an old Crown: after vacuuming metal debris, two thin primer coats completely filled and sealed the cavities. Most crucially, it provides perfect adhesion for subsequent putty and paint layers. During full resprays, this primer bridge prevents delamination.

[LaJeffrey]

Simply put, the primer coat is the universal intermediary in the car paint system. It provides the most direct corrosion protection—imagine wheel wells splashing salty mud on rainy days; without this layer, the metal would bubble within a day. Repair shops love its leveling function, as liquid primer can penetrate and fill even 0.2mm fine sanding marks. During spray gun application, its "double-sided tape" effect on both metal and plastic components is evident—zinc-coated sheets and ABS bumpers sprayed simultaneously still meet adhesion standards. Most importantly, it bridges layers: the vibrancy of the topcoat entirely relies on the primer as a reflective base. I've seen too many cars skip this step, only for their new paint to crack within six months!