For best practice to prepare an aluminum sheet for painting three steps are required that will provide the most assurance that both the paint will remain attached and the metal will be less prone to continue to form disturbing oxidative products on the painting.
Oil painting on metal sheet.
Once the metal has dried dampen a cloth with white vinegar and wipe the surface down.
A metal sculptor may wish to embellish his piece with paint.
If the sheet metal is smooth to the touch you will need to texturize it before painting.
It can be decorative painting on household objects or artistic endeavors on found objects from a junkyard or garage.
The acid in the vinegar will act to etch the metal and help the paint adhere.
This will allow the paint to adhere to the metal.
Apply a wire brush and scraper combo to the metal first to remove all loose paint and rust or to scuff up the surface of aluminum or galvanized metal.
Analyze the surface of the sheet metal.
Using high grit sandpaper or steel wool rub the surface of the sheet metal.
Create a rough surface on the sheet metal.
After removing loose paint first apply an orbital sander using 60 grit sandpaper working up to 100 grit sandpaper for a smooth finish.
Clean new galvanized metal surfaces with a water based cleaner degreaser to remove any oil or and contaminants.
Oil based paints are the most durable.
An artist is always in search of new and inspiring methods and mediums and painting on metal may be the start of a new journey.