Cleaning Sheet Metal Before Painting
Mix water and mild detergent for stubborn areas.
Cleaning sheet metal before painting. For light rust and small areas use steel wool and 80 to 120 grit sandpaper. For every part water combine 0 05 part mild dish or laundry detergent. Sandblasting is an efficient method for removing old paint and rust from a metal object to prepare it for painting. A steel brush also can get much of the crud off.
Try to remove all of the dirt and grime you can. Rinse and let the metal dry. The first step is to clean off loose rust and flaking paint and then apply a rust inhibitive primer. Let it sit for 5 to 10 minutes and then wipe it away with a wet sponge.
If the metal has a rust or mill scale i will typically use one of those bear tex rapid strip wheels to get it down to bare metal first. To properly prepare new metal surfaces use mineral spirits to remove grease and apply a rust inhibitive primer before painting. Mix one part white vinegar with two parts warm water and scrub the metal with a soft scrubbing brush. Inspect the surface for rusty areas and remove all rust down to the bare metal using tools appropriate to the extent of the rust.
Clean the surface the goal is to remove any dust dirt or other particulate buildup that could affect the texture of the metal surface. Opt for something soft to protect your roof s paint and parts. Introduce your secret weapon the secret to painting galvanized steel is white vinegar. Use a cloth or sponge to clean.
You don t need to get down to bare shiny metal just clean off the flakes and powdery surface rust that prevent paint from adhering. Wash the metal thoroughly with a degreasing agent such as trisodium phosphate. For painted surfaces that are in sound condition remove dust with a clean dry cloth de gloss the surface with light sanding and wipe with mineral spirits to ensure good adhesion. I have generally used acetone with latex gloves to degrease but i am not real knowldgeable about it all.
However badly rusted metal areas need more prep work and possibly a special primer. For any areas that don t wash away with pressurized water fill a bucket or other container with water.