Unless maintained, all metal exposed to the elements will rust. Rust is the natural corrosion of iron and iron alloys such as steel when they are exposed to oxygen and water. As the surface rust flakes off, more iron is exposed and this iron will then rust. If the process is not stopped, all the iron will be consumed. When you are talking about gas pipelines, any weakening of the pipe walls is dangerous. Steps should be taken to prevent rust from getting out of control. Rust-resistant paints are the most common defense against the formation of rust on metal that gets exposed to moisture.
Clean the large debris, such as leaves, off the pipe with a cloth.
Go over the entire surface of the pipe with a steel brush. The new paint will adhere best to a surface free of rust and old paint. Prepping the pipes will take some time, but be patient — the better you perform this step the better the end result will be.
Rub down the entire pipe with a clean cloth to remove all the dust created when you scrubbed away all the paint and rust. The new paint will not stick well to the dust. The pipe's surface where the rust has been removed will remain a dull orange color, which is normal.
Place a large piece of newspaper or cardboard between the pipe and the house, adhere it with tape. This will prevent any overspray from the paint from getting onto the exterior of the house.
Paint the pipe. Start at the topmost part and work your way down. Hold the can 6 to 8 inches from the pipe and spray in slow side to side motions. Apply the paint slowly and evenly.
Wait for the first coat to dry. Complete drying may take as long as 24 hours, depending on the temperature and humidity. Allowing the first coat to dry completely will make application of a second coat much more even.
Observe the paint job. Touch up any missed areas or areas where the paint looks thin. If you want to apply a second coat, do that now.
Remove the newspaper used as a shield for the house and enjoy the new, clean look of the gas pipe.
Wear a paper face mask to avoid breathing in the old rust and paint particles.