Cast iron desires a layer of protection, such as a coat of paint, polyurethane, wax or acrylic, against moisture and humidity. Without such protection the metal quickly rusts. It is important to remove layers of old paint and rust only before refinishing so that the new layer of protection can be implemented immediately.
Chemical Stripper
Remove or cover any decorative trim which could be damaged by a chemical stripper.
Brush a thick coat of stripper on the cast iron using a paint brush or sponge. Wear protective rubber gloves, long sleeves and eye protection.
Cover the cast iron using a sheet of plastic and then wait the prescribed period of time as recommended by the producer. This can be around 20 minutes.
Scrape the loosened paint and rust off using a wire brush; wear protective equipment.
Wipe the whole piece down with mineral oil, using a clean white rag, to remove all traces of the chemical stripper.
Repeat Steps 2 to 5 should not all of the paint and rust are removed the very first moment. If there are lots of layers of paint and rust, it might take duplicate applications to remove all of the paint.
Sanding
Eliminate any decorative trim or cover it with plastic or painter’s tape.
Sand the cast iron using a medium-grit sandpaper or steel wool before the paint and rust are eliminated. You can complete this process by hand, using a circular rubbing motion. Alternately, use an electric sander or a handheld rotary tool with a sanding wheel attachment for tight spaces.
Wipe away the dust created by sanding using a damp white rag.
Apply a protective coating, such as paint, lacquer or acrylic, immediately to stop rust from forming.