Stone-Chip Repairs: Fix Them Before They Rust

Where chips appear

Chips gather on the surfaces that face the road: the leading edge of the bonnet, the front bumper, the mirrors, the lower doors and the sills. Motorway driving and following lorries on dual carriageways throw up more debris, and gritted winter roads add loose stones.

Look closely at the front edge of the bonnet in good light. Many cars carry dozens of tiny chips that you only notice when you stand close.

How a chip becomes rust

Paint on a car is built in layers: primer, colour and lacquer. A chip that goes through all of them reaches the metal underneath. On steel, moisture and oxygen then begin to form rust, which spreads sideways under the surrounding paint and eventually shows as a bubble or a stain.

Winter makes it worse. Road salt on wet roads and salty coastal air speed up corrosion on exposed metal. Aluminium panels do not rust in the same way but can still corrode where paint is broken.

• Chips reaching the bare metal are the risky ones
• Rust spreads under the paint around the chip
• Salt and dampness accelerate the process
• Edges and the leading edge of the bonnet are most exposed

What you can do with touch-up paint

For isolated chips, a touch-up pen or small brush with the correct colour can slow things down. Clean the chip, make sure it is dry and free of wax, and apply thin layers. Where there is visible bare metal, a dab of primer first is sensible.

Be realistic about the result. Touch-up paint seals the damage and stops moisture getting in, but it sits in the chip as a small blob and will not match the surrounding finish perfectly, particularly on metallic colours. It is protection, not a cosmetic repair.

When a professional repair is better

If the chips are numerous, clustered on the bonnet or already showing rust, hand touch-up becomes a losing battle. A professional stone-chip repair cleans each chip, removes any early corrosion, fills it, then finishes it so that it sits level with the surrounding paint.

Where a panel is peppered with damage, repainting the panel can give a better result than treating dozens of marks one by one. That might be a partial respray of the bonnet, blended into the neighbouring panels.

Catching it early

Inspect the front of the car every few weeks, especially in winter and after long motorway journeys. Wash regularly, because grit left on the paint can scratch and hide new damage. Treat chips as soon as you see them rather than waiting for a rust bubble to appear.

At Banks of the Tyne in Hebburn we carry out stone-chip repairs as part of our paintwork service. We will tell you honestly whether a chip repair will do or whether the panel needs more.

Reducing future chips

You cannot avoid chips completely, but you can reduce them. Leave a bigger gap behind lorries and vehicles that shed grit, and avoid driving close behind gritters. Keep the paint in good condition with regular washing and an appropriate wax or sealant, which can help the surface resist small impacts.

Clear protective films are another option some owners choose for exposed front areas. If you are thinking about it, ask a specialist what they would recommend for your car.

Frequently asked questions