When to stop before burning through clear coat

This is a very tricky question. There is no easy way to tell when you’re about to burn through clear coat. It comes with experience, but even the most experienced detailer can burn through clear coat. Paint film thickness can be measured in two ways. The standard measurement is in mils. A mil is equal to 1/1000 of an inch. A factory paint job can measure between 4-6 mils. Clear coat is usually between 1.2-2.2 mils. Thats such a small measurement to work with!

The metric way to measure film thickness is in microns. A micron is one millionth of a meter or 1/1000 of a millimeter. There is 25.4 millimeters in an inch. The average film thickness on a factory paint job is 98-122 microns. Personally I think reading in micron measurement gives a more accurate reading because it is in a much smaller measurement than mils.

Now, for buffing you don’t necessarily need a paint thickness gauge, because buffing doesn’t wipe out microns (unless you don’t know what you’re doing). I would strongly recommend getting one if you buff cars everyday. Buffing correctly should only remove around 2-3 microns. When you are buffing, make sure you are using clean pads, not too fast RPM, having enough product on the pad, have the pad start on the panel, keeping the buffer flat on the panel, and not putting too much pressure on the buffer machine. There is so much to be aware of when you’re buffing. Just make sure you are using proper techniques when buffing.

All above is easier said than done. That being said, if you happen to burn through clear, don’t panic. We’re all human and make mistakes, I prefer to call mistakes learning opportunities. Notify the owner and own it. It’s better to be honest and let them know. Some people may be okay with it and will let it go. Others would want it fixed. To fix burned through clear, the whole panel will need to be refinished. Most manufactures say you can remove 25% of the clear coat finish to maintain warranty. A couple things to keep in mind while buffing to avoid burned through clear coat:

Tape over body lines because they tend to have less clear coat on them

Always turn on the buffer with the pad on the panel

Keep buffer at a low RPM until you feel more comfortable speeding up

Buff in sections to maintain even passes along the whole panel

Avoid keeping the panel from getting hot. Move at a steady pace and keep the buffer flat