There is nothing more upsetting than the helpless feeling when you discover paintwork or panel damage to your car. Let's face it; cars are not cheap and are probably the second largest investment you will ever make besides property.

How many times have you been washing or polishing your vehicle and have discovered a dent or scratch from some fellow motorist who had carelessly 'parked' their vehicle or shopping trolley against your pride and joy, leaving a dented door or bumper as evidence of their carelessness? The next point of contention is when you think of your insurance claim, the problems are just as bad.

First you'll need the three estimates to do the repair, then there is the time factor — you will be without a car for a while during the repair — and then you need to consider the insurance excess payment.

Having stated the negative facts of repairs, the next option is, of course, to attempt the repair yourself, but do remember that badly creased, torn or fatigued metal repair should, however, be left to the professionals.

Removing the dent

Start by inspecting the damaged area and see if there is easy access to the inside of the panel. Double panels are not easily repaired unless you are a professional and have all the required specialised equipment. Door panels can be repaired more easily, as the inside of the door is exposed once the inner panels are removed. On a mudguard, you should remove the wheel to gain easy access to the damaged area. Work from the inside of the panel, pushing the dent outwards, starting from the outer perimeter of the dent working towards the middle where the dent is at its worst.

Try to avoid using an ordinary hammer as this is likely to leave semi-circular coin-like marks in the metal. If you purchase or borrow a set of panel beating tools, or even a panel beater's hammer and dolly, you can, with patience and care remove a dent successfully.

A bag of sand clenched in your fist or a soft headed hammer will also eliminate damage to the paint work. The easiest way to use the hammer and dolly is to use the dolly on the outside and the hammer on the inside of the panel to tap the dent lightly and repeatedly.

Listen carefully to the sound that the dolly and hammer make when the hammer strikes the dolly through the metal. A clear ringing sound will be heard if you hit the dolly correctly, however, if you miss the dolly position through the metal, a dull thud will be heard. Keep the hammer's head square to the surface of the metal, as any angle blows will show up as dents to the outside. Also try not to hit too hard as this will stretch the metal, causing more damage that will take a lot of work to get rid of.

Sanding and filling

Once you have got the contour more or less right, sand off the paint and rust in and around the dented area. Sand lightly so as to remove the 'high' spots only. These high spots are the metal peaks that stick out above the general surface of the dent. Once you have got the surface more or less right, sand off the paint in and around the dent so that the entire damaged surface is cleaned down to bare metal. Use 120 or 180 grit waterproof abrasive paper.

Use a two-part body filler to cover the uneven surface. Stir the body filler in a container until all the liquid is absorbed. Transfer an amount of body filler about the size of a golf ball to the surface of a flat plastic plate (a lid of an ice-cream container is ideal).

Now add about 10-15 drops of hardener to the body filler paste and mix it well. Use the straight edge of the piece of plastic to smear the mixture onto the surface to be filled. Keep the thickness of the layer about 3-5mm and as smooth as possible. Allow it to dry hard before applying the next layer. Continue applying layers until the repaired surface is proud and sticks out slightly above the undamaged surface. If, while you are applying the filler, it starts to appear crumbly, it has become too dry to apply. Throw away the remainder and mix a new batch.

Spraying the surface

When the body filler has dried, sand it smooth using a sheet of 150 or 180 grit paper. Using plenty of water and not too much pressure, feel the body contours through the paper with your fingers. Use more filler as needed to fill any holes which might appear and repeat the process. You can progress to 220-230 paper to ensure a smooth surface finish — remember that any imperfections will be emphasised by the paint. Paint doesn't hide poor preparation or pin holes in the body filler, but rather makes them more obvious.

Once the surface smoothness has been obtained, wash off the area and allow to dry. Mask off the surrounding area with masking tape and newspaper. Spray on a thin layer of grey primer and examine the surface area for blemishes. There are bound to be small pinholes caused by air bubbles in the body filler. Fill these pin holes with spot putty using a spatula. (spot putty is for repairs to pin holes only and is not to be used to fill big dents or holes). When the spot putty has dried, use 400 grit abrasive to rub the surface down lightly until all the marks are no longer visible.

Spray another coat of grey primer on the surface until you are satisfied with the final surface finish. Wipe dry the prepared surface, removing all dust and dirt. Start by shaking the aerosol can for at least a minute or until the ball inside the can moves freely.

Hold the colour aerosol can about 25-30cm from the surface and move your hand from left to right across the entire width of the area. Try to overlap the previous stroke by at least one third. If you hold the spray can too far away from the surface, you will see a finish that looks like a peel of an orange. This is because the paint is almost dry before it hits the surface, and the droplets cannot flow into each other to form a dry shiny surface.

Finishing touches

If you hold the spray can too close to the surface and move your hand too slowly, the paint will run down the surface leaving too thick a surface spray and tear drops. Practice on a piece of cardboard until you achieve a smooth shiny surface and smooth hand flow.

Remember that dust and paint fumes are harmful to your health and you should wear a dust mask or respirator when spray painting. If you are sensitive to paint fumes, use a mask even when spraying with an aerosol. By working slowly and carefully, you should get a surface which you can be proud of, although the above is more focused on small patch repairs. Larger jobs should be referred to a professional or attempted with a compressor and spray gun kit.