There are lots of metal surfaces around your home which might, at some point, need stripping and repainting. These include Radiators, guttering, gates, railings and drainpipes. In most cases metal objects will be painted with an oil based paint which helps to reduce corrosion. Try giving the paint a good clean first to see if this will bring back the original shine and colour. If this does not work, your best bet is to strip back to the base metal and repaint.
Make sure that the surface you plan to strip is actually metal. Some moulded fireplaces can look like cast iron, but actually be made from plaster on a wooden frame. Tap the area and listen to the sound produced or scrape a small test area back to the base material to find out.
Chemical Paint Stripper
Chemical paint stripper is the best thing to use when stripping oil based paint from metal. Heat guns will usually heat the metal before softening the paint and are therefore not much use. A gas blowtorch could possibly be used, but you run the risk of cracking cast iron objects, as well as the fire risk involved.
Choose the correct chemical paint stripper and apply as directed. Leave this for the recommended time and carefully strip the paint. Once the majority of the paint is removed, clean any remaining paint with a wire brush.
If the base metal is showing signs of rust, paint it with a Rust Converter or Rust Inhibitor before cleaning well with a wire brush and washing with white spirit. Your metal surface is now ready to be primed with a Zinc Phosphate or Red Oxide Primer and then repainted.
Safety
Always wear protective goggles when removing paint or rust with a brush or power tool. Small chips of paint and pieces of rusted metal can fly into unprotected eyes.
Wear heavy duty rubber gloves when using chemical paint stripper. Several types will cause skin irritation. It is also a good idea to work in a well ventilated room.
Some old paint may contain lead. If you know or suspect the paint you are removing contains lead, always use a chemical paint stripper rather removing the paint by sanding or grinding. If grinding or sanding is your only option, wear a dust mask and goggles, and make sure the room is well ventilated. Using wet and dry sanding paper will also reduce dust.