How does a clay bar clean paint?
It grabs whatever stands proud of the clear coat as it slides across a wet panel. Specks that a wash mitt rides over catch on the clay and stay in it, leaving the surface smooth to the touch.
Carmakers use it as a standard repair step. Volkswagen’s bulletin 00-17-06 has technicians wash the car, feel the paint by hand for a rough or gritty texture, and work only those areas with clay, using car shampoo as the lubricant and repeating as needed. Chrysler’s overspray bulletin 31-001-13 does the same job with a mild clay bar and a detail spray, one 305 mm (12 in.) square at a time, and moves on to machine polishing only if the clay leaves overspray behind.
What are the rules for claying without scratching?
Keep it wet, move it in straight lines, and keep its face clean. Clay is gentle only while it glides; dragged dry or loaded with grit, it can mark the paint it’s cleaning.
| Rule | Source |
|---|---|
| Work while the lubricant is still wet | Chrysler 31-001-13 |
| Move the bar in one direction, never in circles, “as it will create scratches” | Chrysler 31-001-13 |
| Knead the clay periodically to reduce scratching, and store it in a container | Volkswagen 00-17-06 |
| Throw the bar away when contamination becomes excessive | Volkswagen 00-17-06 |
| Wipe the residue off with a microfibre cloth | Chrysler 31-001-13 |
Because clay can mark paint when it’s misused, the shop’s coating packages follow it with machine polishing, the step defined under polishing.
Why does clay matter before film or a coating?
Anything left on the paint ends up sealed under it. 3M’s PPF installation guidelines list a clay bar as the fourth vehicle preparation step, after adhesive cleaner and glass cleaner, to take surface contaminants off the paint before film.
After a winter on BC roads treated with salt and sand, run a flat hand over the washed paint the way Volkswagen’s technicians do; any patch that feels gritty is a patch for clay. Clay comes after the chemical steps described under decontamination wash and iron remover, so it only has to collect what they couldn’t dissolve.
Where clay shows up at Brookswood Tint
In the opening steps of both coating and film work. On the ceramic coating menu, clay sits between the decontamination wash and the first machine polish in all three packages, and paint protection film is never laid on paint that hasn’t been decontaminated.
Whether a car also needs polishing after the clay depends on what’s left in the clear coat. For coatings, that’s answered in correction ahead of a coating; for cars fresh off the transporter, in paint correction on new cars.