Carbon steel pipes consist of an iron and carbon alloy that is able to be bent into shapes during manufacture without reducing its high tensile strength. It is important to protect the steel surface from corrosion due to the iron ferrite composition that will rust through oxidization from water contact. The pipework that supplies fire sprinkler systems is often carbon steel, and requisite strength components such as cam and crank shafts in aircraft and cars use carbon steel pipes and tubing. Painting carbon steel pipes to effectively avoid corrosion requires the use of the correct primer and paint.
Things You'll Need
- Wire wool
- Hand brush
- Solvent-based cleaner
- Zinc phosphate paint primer
- Stir stick
- Polyurethane acrylic paint
- Safety glasses
- Protective gloves
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Use wire wool and remove all surface rust from the carbon steel pipe. Sweep up any rust particles using a hand brush to keep the work area clear of dust.
Use a solvent-based cleaner and a cloth to scrub off all grease and oil stains from the surface of the pipe. Wipe the cloth over the entire surface of the pipe to collect any dust or rust particles that remain. Allow the carbon steel to dry.
Open the zinc phosphate paint primer and use a stir stick to mix the primer to a uniform consistency. Use zinc phosphate paint primer because the zinc forms a barrier that acts as an anode in the electrochemical corrosion process and deflects pitting on the carbon steel.
Load the primer onto a paintbrush and apply a thick coat to the carbon steel pipe. Allow the primer to dry according to the manufacturer’s instructions.
Use a stir stick and mix the polyurethane acrylic paint to a homogeneous color. Use a paintbrush and apply a coat of paint to the pipe surface. Wipe up any paint that enters the ends of an uninstalled carbon steel pipe in order to prevent pipe contamination.
Allow the first coat of paint to dry according to the manufacturer’s instructions. Generally, most acrylic paint is ready for a following coat after two hours. Paint a final coat of polyurethane acrylic over the surface of the carbon steel pipe to complete the task.