I caused a minor scrached on the back bumper of my 08 mazda 3.
what do you guys recommend to repair it.
thanks in advance.
Depends on the severity of the scratch. The deeper it goes, the harder it'll be to fix "properly".
If it's not past the clear coat, an OTC swirl and scratch remover should work fine to cover it up. QUIXX scratch and swirl remover can actually polish minor scratches out (in the traditional sense), but it takes great care to apply properly lest you make the situation worse (i.e. hazing up the clear coat).
If it is past the clear coat, you'll probably want to clean it up with an alcohol wipe, apply some clear coat touch-up with a toothpick (as little as possible in a single application; multiple applications are better than a single application, and don't go proud of the surrounding paint or you'll have to wetsand it back down), maybe use QUIXX after that, then wash and wax the area.
If it's past the base coat, same as above but start with color-coded touch-up.
If it's past the primer, seek professional help unless you're feeling particularly brave.
This is all MHO, too. Search the forums and you'll find other opinions, too.
Pics help, too..
