Painting metal is different than painting other surfaces. For one, paint won’t stick as well to a metal surface as it will to wood or plaster. Also, metal is prone to oxidation and rust. Because of this, it’s essential to use a paint that is formulated especially for metal. These paints come in oil-based and water-based versions. Oil-based paint is trickier to work with, but the results are longer lasting. Water-based acrylic paints come in spray paint versions and can be more forgiving overall. Regardless of what type of paint you choose, completing the appropriate prep work is essential. Follow the steps below for the best results.
Equipment / Tools
- Shop rags
- Scuffing pads
- Dust mask or respirator
- Paint brush
- Water-based acrylic paint for metal
- Oil-based paint for metal
- Rust Remover
- Mineral spirits
For starters, you’ll want to make sure you protect yourself. Before you proceed, put on a dust mask or respirator, protective goggles, and gloves anytime you work with metal. Also, be sure to work on any metal project in a well-ventilated area.
Prep the Metal Object for Paint
Use a wire brush to remove any loose or flaking paint. Next, continue scraping the metal with the wire brush to remove as much surface rust as possible. If the wire brush alone is not effective, consider using a wire brush attachment for your drill for highly degraded surfaces. Be sure to wear earplugs and follow all the previously mentioned safety protocols.
If the rust has penetrated deep into the surface, soak the object in an appropriate rust remover and follow all steps as specified by the manufacturer.
Take a damp cloth and wipe the surface to clean any dust, debris, or rust that’s leftover. Avoid using excess water, since this won’t effectively clean metal.
To make sure all grease has been removed, wipe the metal with a shop rag that has been coated in acetone. Allow the acetone to dry off before proceeding.
If the metal doesn’t currently have paint on it, the final prep step is to take a scuffing pad and rub it along the metal. These pads will lightly etch the surface of the metal, which will allow the primer to stick more effectively. The pads will also make sure the surface is as smooth as possible.
Prime the Metal Using the Right Primer
If you were unable to remove all the rust in the previous step, you’ll want to coat the metal with a zinc-chromate primer that is specifically for coating rust.
After you have coated the area with this special primer, immediately apply a coat of self-etching primer. Remember, it’s important that this primer should be specifically for metal and has a self-etching component. If you’re unsure, read the label to see if metals are listed as an intended surface. The last consideration for primer is to be sure the primer is compatible with the paint you want to use. A primer can be either oil-based or water-based.
Next, follow the instructions on the label since different primers will have different drying and cure times. If the metal is intended to be outdoors, consider adding a second layer of primer to help prolong metal oxidation.
Apply Spray Paint for Metal
The easiest way to paint metal is to use a can of spray paint. To use spray paint:
- Shake the can several times to mix the paint.
- Spray the object using long, sweeping motions. Be sure to hold the can 6 to 12 inches away from the metal, which will prevent the paint from pooling. If you notice excessive dripping, wipe clean, back up, and start the process again.
- Make sure you don’t hold the spray can in the same spot. The can should always be moving in sweeping motions to prevent the paint from dripping.
- For best results, apply up to three thin coats of paint and allow the paint to dry before applying an additional layer.
Apply Paint Using a Brush
If you want a longer-lasting finish, try painting metal using oil-based paint in a can. Spray painting is easier, but spray paint does not create as hard of a finish. By painting the metal object with a brush, you can create a thick surface that will be more durable.
- Open the can and mix the paint according to the manufacturer's specifications. The paint might be too thick and need to be cut with some mineral spirits.
- Once the paint is a desirable consistency, use a high-quality natural bristle brush to paint on a thin layer. Oil-based paint tends to dry smooth, so you won’t need to worry about brush strokes if you apply a thin layer with the right type of brush.
Finally, allow your metal object to cure for 36-48 hours before moving it. Make sure the object is in an area that won’t see extreme temperatures and won’t’ be in direct sunlight while it’s drying.