Using a Clay Bar on Automotive Paint

Wash your car and look closely at the paint surface. Run your finger across it. If this finish is anything less than pristine, you're going to notice things with your finger. Things on the paint surface that aren't visible but still there, stuck to it, embedded, adhered to the paint in a fashion that keeps these particles from being removed by a typical washing.


What's happened is the sharper, pointier, stickier things in the air have actually jammed themselves into the first layers of paint. This is no longer a surface-only dirt issue that a thorough washing can handle, as a wash mitt or sponge doesn't have the grabbing, grippiness to pull these things out. So, you're left with a clean car that's still covered with the same selection of glass fragments and fibers, rail dust (little metal slivers emitted by the interaction between train wheel and rail), minute chunks of gravel and Earth byproduct. Enter the clay bar.


We can hear you asking what clay has to do with car washing. Imagine this—the act of pulling a soapy sponge across your car's wet surface while washing, with the stiction capacity (just made that up; the degree to which something adheres to and pulls on a surface when interacting with it laterally) amplified to where the pulling and stiction level is great enough to remove minute contaminants embedded in the paint. That's what a clay bar does: cleans the paint surface down to its pure paint self, sucked clean.


Automotive paint clay is a very particular grade of fine clay, not too unlike some clays used in modeling. Used by car care pros for ages and long a back door secret of the car care industry, insiders have brought the clay bar and its usefulness to public attention. Used with a lubricating spray (often a detailing spray) that allows the otherwise super-tacky clay to glide without marring the paint itself, automotive clay can be the tool to step from "just washed" to "ready to polish and wax."


Using clay is remarkably simple. Starting with a freshly cleaned vehicle, wet a section of the vehicle's painted surface with the clay lubricant and rub the clay on the paint in a random fashion. You don't want to use the whole wad of clay—a half or a third of what you're supplied is a good place to begin. As you use the clay, "rotate" it frequently, turning it as it fills with the things it pulls from your paint. You want to have fresh clay touching the paint. Dry off completed portions of paint with a cotton towel. Again, work by sections. Important: listen to the clay. As it slides across the paint on a film of lubricant, you'll hear its contact with the bad things in the paint. As fewer things are left to pick up, the bar will make less noise and you'll feel it slide more easily. You can treat the whole vehicle this way. Run your fingers across the paint after working over a portion of the painted surface and you'll be able to deduce the difference, by touch.