0

Often surfaces are sanded before painting to increase adhesion of paint to the surface. I have never seen an explanation as to why this actually results in much stronger adhesion of paint to the substrate.

Is this increased adhesion actually the result of sanding creating micro grooves in the surface that increases the amount of surface area the paint can bond with?

Thank you.

Sophie
  • 3

1 Answers1

0

Sanding removes grimy dirt, which interferes strongly with paint adhesion. And, as you point out, it increases the surface area for the paint to grab on to- but it also creates "undercuts" in the surface which the paint oozes into and then, once the paint sets up, the undercuts are trapped in the paint film which then cannot be pulled free from them.

niels nielsen
  • 92,630