How to Repair a Chip in Powder-Coated Steel

Powder coat chips. Usually on an edge, usually because something hard met it at speed, and almost always at the bottom of a leg. The chip itself is cosmetic. What it starts is not, and the difference between a ten-minute job and a respray is whether you deal with it this month or in two years.

Why a chip matters

Steel rusts when it has water and air. Rust takes up more room than the steel it came from, so it does not sit politely inside the chip. It expands and pushes outward, lifting the coating from underneath. That is why an old chip has a halo of flaking coat around it and a fresh one does not.

The coating is a barrier. One hole in a barrier is still a barrier for most of its area, which is why nothing dramatic happens at first and why people leave it.

What you need

• A cloth and warm water with a drop of washing-up liquid.
• Isopropyl alcohol or methylated spirit on a cotton bud, for degreasing the bare metal only.
• A small piece of fine abrasive paper, around 400 grit, or a fibreglass scratch pen.
• Air-drying touch-up paint in roughly the right colour.
• A cocktail stick or a fine brush.

Not a brush from the paint tin lid. The lid brush holds far too much paint for a chip and gives you a blob with a raised rim that catches light from across the room.

The repair

1. Clean. Wash the area, rinse and dry it fully. Any grease under the paint means the paint lets go later.
2. Check the edges. Run a fingernail around the chip. If coating lifts, it is already undermined. Lift the loose flakes away with the nail or the corner of the abrasive paper until everything that remains is firmly attached. This feels like making the damage bigger. You are making the repair permanent.
3. Deal with any rust. If the bare steel is orange, take it back to clean grey metal with the abrasive paper or the scratch pen. Paint over rust is a delay, not a repair.
4. Degrease. Wipe the bare metal with alcohol on a cotton bud and let it flash off. Keep the alcohol on the bare spot and off the surrounding powder coat, which solvents can soften.
5. Paint thin. Dip the cocktail stick, wipe most of it off, and lay a small amount into the chip. You want it level with the coating, not domed above it. Let it dry.
6. Second coat if needed. Paint shrinks as it dries. A second thin coat beats one thick one every time.

Where to look before a chip finds you

Powder pulls back slightly from sharp edges as it melts in the oven, so the film is thinnest exactly where a piece meets the world. Twice a year, look at:

• The bottoms of legs and any foot that drags when the piece is moved.
• A ring stretcher or footrest where heels land.
• The outside of every bend.
• The crown of a weld.
• Base plates, where mopping water sits.

On the Stool No. 1 that means the three feet and the ring. Four kilos of stool gets lifted and dropped a lot, and the ring is where shoes go.

Prevention, which is cheaper

• Felt or rubber under every foot. This protects the coating as much as the floor, and there is more on the choice in protecting floors under heavy furniture.
• Lift rather than drag. Dragging grinds the thinnest part of the film against grit.
• Dry the feet when you mop, rather than letting a piece stand in a wet patch. This is the main route to rust indoors, covered in why powder-coated steel rusts.

When touch-up is not the answer

If a panel has many chips, if coating is lifting over a wide area, or if rust has spread under the film beyond the damaged spot, touch-up paint is a delay. The real fix is stripping the part and recoating it. That is a workshop operation and it is worth doing on a piece you intend to keep for decades.

Reality check

• Sealing bare steel is the job. Hiding the chip is not.
• Paint over rust fails. Always take it back to clean metal.
• Thin coats. A blob is more visible than the chip was.
• Loose coating around a chip must come off or the repair lifts with it.
• Ten minutes now, or a respray later. Those are the two options.