Body filler is often used in unscrupulous ways and the results passed on to unsuspecting consumers. Instead of adhering to approved, industry-accepted standards, some shops make poor repairs and misuse body filler to disguise the damage . Often these repairs are undetectable by visual inspection alone. A quick and simple way to test for such repairs is by using a magnet.
Glue a piece of protective felt on the face of a strong magnet. Use silicone sealer to bond the felt to the flat face of magnet and let it set for several hours.
Open the hood of the car an inspect where the fenders bolt to the radiator core support. Often body damage is easy to detect in this area. Paint over-spray and masking lines are sometimes left behind during a collision repair. Locate a section of unrepaired metal and test the magnet strength as it bonds. Use this as a guide when testing other parts of the car.
Raise the trunk of the car and inspect the inside of the outer panels. Move any plastic or carpet liners away from the sides and look at the panels. These are a direct reflection of the outer panels and are easy to inspect. Any damage or creases are a sign of repairs, even though the outside is smooth.
Apply the magnet to various locations around the car. If there is a significant amount of body filler, the magnet will pull with varying degrees of strength. In some cases, if the filler is very thick, if will not stick at all. Avoid any cars with repairs such as this.
