There are two main types of conduit found in homes today. Metal conduit, also known Electrical Metallic Tubing (EMT) is commonly made of stainless or galvanised steel. PVC conduit is made of a plastic-like material that is a bit lighter and easier to work with than EMT. Painting either type of conduit may be necessary to help it blend in with its surroundings (or to simply decorate the tubing to make it look better).
Remove any rust or film from the conduit using a wire brush or sandpaper.
Apply water-based cleaner/degreaser to a rag and thoroughly clean the conduit that you wish to paint. Remove any excess dirt, oil and dust that may have accumulated on the tubing.
Allow the metal to dry and apply a small amount of vinegar with a clean rag.
Wait for the surface of the conduit to dry again, and then apply latex primer with a paintbrush. Apply the primer with even strokes, covering the entire area to be painted.
Allow the primer to dry according to the manufacturer's specifications. Apply two coats of latex paint with a clean brush and allowing the first coat dry before applying the second. Finish the paint job according to the directions on the paint container.
Clean the PVC conduit with a commercial cleaner or degreaser. Wash excess cleaner off with water and allow the PVC to dry.
Prepare the conduit for painting by lightly sanding it with fine-grit sandpaper. Sanding the PVC will help the paint stick to the tubing better. Remove excess dust from the conduit before moving on.
Apply a coat of primer to the conduit using a paintbrush and latex primer designed to be used on plastics. Allow the primer to dry before painting over it.
Apply one or two coats of latex paint to the conduit with a clean paintbrush. Let the first coat dry before applying the second and follow the directions on the paint can. Let the paint dry before touching it.
A stiff-bristle paintbrush may be helpful in applying paint to flexible metal conduit.
Be careful when using commercial cleaners and degreasers. They can be harmful to humans and animals. Paint in a well ventilated area to avoid inhalation of paint fumes.