Do I Need to Sand & Prime a High Gloss Surface?

Glossy Surfaces and Paint

• Primer and paint can't adhere completely to a nonabsorbent glossy or slick surface. The surface of glossy paints, plastics and metals all must be made slightly rough so the paint can adhere. Glossy latex and oil paints can't fully absorb the primer coat or paint, which makes these surfaces more prone to blistering, peeling and flaking. An overly rough surface remains rough and dull after painting, while a smoothly sanded surface becomes smooth after primer and paint application.

Sanding Methods

• Two options exist for roughening the glossy surface. Liquid sandpaper products work on painted wood and drywall surfaces. These products work as a solvent. Simply wipe them over the wall surface to remove the gloss and reveal a surface the paint can adhere to. Sandpaper is a suitable choice for all glossy surfaces. Use a fine-grit paper to sand only until the gloss is dulled, but not until the surface feels rough. A wire brush is sometimes necessary to dull glossy metal.

Purpose of Primer

• Primer provides an even surface for paint application, which results in a smoother surface with more even color coverage. A latex primer works best on drywall because it creates a moisture barrier between the drywall and the final paint coat. Oil-based primers are suitable for wood, plastic and metal because the oil adheres better to these materials and doesn't peel off later. Primer covers any surface imperfections and smooths out any light roughness left by the sanding process.

Adding Shine

• You can add the gloss back to a properly sanded and primed surface when painting. Use a glossy paint to add some shine to the surface if you wish. A semi-gloss paint provides a light shine, while a high-gloss paint adds full gloss to painted interior walls. A final coat of clear glossy sealant on metal, plastic and wood provides a high degree of shininess to the surface. Glossy paints may not reach their full shine potential if applied over improperly sanded or primed surfaces.