clay bar and coumpound

[S2K]

I've been reading on here to wash (of course) and then clay bar before starting to compound using a DA polisher. My question is why do you need to clay? Won't the compound take everything off the clay will?

 

[Toddzilla67]

Though I'm not 100% sure, my guess is that you want to use less abrasive clay first to clean all the impurities from the paint instead of using compound and leaving swirl marks and driving those impurities further into the clear coat. I recently clayed the whole car and just used compound where I had some scratches and magnesium chloride stains that needed attention. I followed with a coat of RejeX.

I'm sure there are many here that will give you a better answer than I have.

 

[kronos]

Clay removes embedded contaminants from the clear coat. If you polish before claying, you run the risk of scratching your paint with those contaminants. However, you don't always need to clay first. Try the sandwich baggie test. After washing your car and while it's still wet, put your hand in a sandwich baggie and glide your hand across the paint. If you feel any grittiness, you need to clay.