Car body filler is a chemical compound which allows us to fill holes and chinks in the bodywork of our vehicles at a relatively low cost. It makes homes repairs easier and cheaper. There are some rules which apply to using car body filler and people often make the mistake of using it incorrectly. Its best bedding is always metal or fiberglass and there should ideally be no air between the filler and the material it is bedded into.
It is vital to remember that car body filler is a compound chemical mixture of two components. In order for it to properly cure, it must be mixed correctly. The most common brand name for body filler is Bondo, but while Bondo is a brand name, it has become synonymous with generic brands too. Always follow the mixing directions when using car body filler. The right proportions of each part must be mixed together.
Always use a mask when you intent to mix body filler. The fumes are strong and potentially toxic, so use a form of protection on your face. A large piece of stiff card is usually a good product to mix the filler on. It doesn’t encourage hardening and it is disposable. You can use thin plastic or Perspex too. For mixing the two parts of the compound you can always use a wooden stick from an ice pop or lollipop. Use another piece of stiff card to scoop some filler out of the can and shut the lid. Take the tube of hardener and spread some across the filler and mix gently but quickly. Fold the two parts together until the marbling has disappeared and the mix is all one color. Be very careful not add too much hardener because it will cause the mix to cure too quickly. Mix until the compound is a light gray and the consistency of whipped cream.
You will need a strong piece of thin plastic, or a credit card sized piece that you can use to spread the mixture. You must make sure the potential surface is ready to accept the filler before you mix it. By then you should have sanded the body work down, wiped it with a clean tack cloth and smoothed it out using fine damp wet and dry sand paper. Once you have made certain it is clean, dry and ready, only then should you mix the car body filler to complete your hole or dent repair. Scoop up a little filler on the plastic card and spread it evenly and consistently onto the area of the body work that needs it. As you spread, any excess will be picked up on the card and taken along with it where you can rework it over the area if you need to. Once you have smoothed out the surface where the filler has been applied, leave it to dry hard before you sand it down and apply any further treatment.