Alex poses a great question on when wet sanding is necessary to remove defects from paint:

Hi there, Pros of DI!

I had just got through reading Todd Cooperider’s walk-through of a 2008 Crystal Metallic Red Corvette that he had just done, and I noticed that at one point, he found himself wet sanding a portion of the driver’s side skirt. My questions is: At what point or how damaged does the paint/clear have to be where we find ourselves finding the need to wet sand the surface prior to compounding and polishing?

Thanks,

Alex

Hi Alex, and thanks for submitting this great question.

First of all let me start by saying that wet sanding is definitely an advanced process for paint correction, and I only recommend it for those already skilled at paint correction with a rotary polisher.

To be honest, I think that for a lot of us detailers that perform wet sanding services, we just know when by looking at the defect based on experience. It depends on a lot of factors like how severe the defects are, where they’re located, how hard the paint is that we’re dealing with (softer paint can be corrected most of the time without having to be as aggressive), and a variety of other influences as well.

I always prefer to take the least aggressive method first in the interest of clear coat preservation. If I think there’s a good chance of removing the defects by just machine polishing, then I will try that route first.

If I am already using a heavy cut compound with a wool pad though, and I’m barely making a dent in the defect, then I will bump up to the more aggressive method of wet sanding, followed by multiple polishing stages to refine the area that was sanded.

The most important detail here to remember though is that you always need to be cautious when sanding. If you don’t have a paint thickness gauge to monitor how much clear coat that you’re removing, then I would recommend only very light sanding otherwise you run a serious risk of striking through to the base coat (and then a re-paint is in order).

To read more detailed information on wet sanding, and to see some amazing examples of defect removal and paint leveling that wet sanding produces, I recommend that you check out Rasky’s articles:

• 1966 Corvette Sting Ray 427 Gets Wet Sanded and Buffed to Perfection
• Full Wet Sanding of a 2005 Acura RL

But to get back to your question Alex, knowing “when” to wet sand really comes with experience. Once you know how severe of a defect that you’re capable of removing with a rotary polisher, then you’ll know when you’ll need to take the next aggressive step with wet sanding.

I hope this helps. If you have any additional questions or comments, please post your reply below.