Video: The Flex 3403 Rotary Buffer – How to remove Sanding Marks after Dampsanding Orange Peel

[Mike Phillips]

Hey Mike, so your readings were all over the place on this one with the PTG and you were guessing it was because of body filler. What do you do in this case where you cannot get an average paint thickness since you can't tell if there is one are that is thinner than the other?

I don't know if you've ever read anything where I talk about making the Go or No Go decision? That's what I would do for a project car like this, talk to the owner, if possible talk to the painter, try to find out how many coats of clear were sprayed, the goal being to feel confident that there is enough clear to safely sand, compound and the polish.

The Paint Thickness Gauge is a useful tool but I use it as an "indicator" not the final decision maker, that comes from me.

In the real world, this car should have been sanded a few days after it was painted, at least that's when it would have been the easiest to remove the sanding marks out of the clear coat.

For anyone reading this that's thinking about sanding down any car and then buffing it out, before you do, read through this article.

Wet-sanding - Fresh Paint vs Factory Paint

Traditionally, how thick is factory CC paint and how do you handle it if the readings do vary quite some bit and you plan on sanding?

Let me answer the above question in reverse, that is the second portion of the question first,

If the car has a factory clear coat finish, then I probably wouldn't be sanding it down because of the risks involved not only at the time of the wetsand, cut and buff, but also long term.


Now the first portion, I've been told my a friend of mine that is a consultant to automakers on paint and polishing that the basecoat needs a minimum of 1.3 mils of clear to protect it from deteriorating, fading and clear coat failure.

I've always read and been told that the factory clear coat, that is just the clear layer of paint is approximately 2 mils and that for correction work you can safely remove down to .5 mils and theoretically, with regular, good maintenance, the finish will still last over the service life of the car.

2.0 mils
-.5 mils
= 1.5 mils
~~~~~~~~~~~~~~~~
Minimum required = 1.3 mils

So there's still a little wiggle room in there but keep in mind, you don't have to remove .5 mils with any process, you can turn the job down, or use the least aggressive product to get the job done.


When I've been approached to sand down factory clear coat finishes on pristine, brand new cars, it's usually because the owner of the "new" car doesn't like the Orange Peel texture in the paint and they "hear" about the process of wetsanding and without doing a lot of research decide to hire someone to do this to their car.

What I do is educate them using information from the article above and recommend they find someone better than me to do the work because I don't want the risk, nor the headache.

I know guys that sand down factory paint jobs for money, I know guys that sand down factory paint jobs for the purpose of creating a write-up, different goals in mind. For the guys that will do this on any factory car for money, I say more power to them...

Can I do it? Yes. Do I want to do it for a fee or for a write-up? Depends upon the owner and the project but in most cases I would pass.


One thing for sure, most, if not the majority of people I've talked to that own a car they want sanded, before talking to me don't know what's involved, don't know the factory clear on their car is thin and hard, and very little else... all they know is the paint on their new car has orange peel and they've "heard" of the term wetsanding.

My guess is a lot of detailers that are not online will take the job for the money... just a guess... who knows how qualified they are either in the knowledge department or the skill department.


Good questions!

[Andrew C.]

Ah thanks for the great advice Mike! I wouldn't ever think about sanding down an entire panel (or car) of factory clear. I was kinda wondering this more in terms of doing spot corrections that would require sanding. I haven't ran into it yet, but I guess if the readings across the panel were pretty random, then the best course of action would probably be to not sand at all and get it as best as you can by machine. Even though I don't believe spot sanding would remove .5 mils of clear (using 2000grit max), I probably wouldn't risk it if I ever ran into that scenario.

Once again, thanks for the help

[Wills.WindowsAndWheels]

Another very good article.

What i like so much about these articles is you start off with something like, in this case...orange peel removal...but then it gets down into the nitty gritty of what about the edges...what do you do along the tape lines....what about factory paint etc etc etc.
I like how it branches off into sub categories

So Mike, if by chance you do come back to this article...i see its about 7 months old now....has any situation arisen since the time of this article to where you did sand down a factory clear coat to remove orange peel?

[sjb89]

Does anyone make a 6 inch convulated foam pad (waffle type that 3m sells) and backing plate that will fit the FLEX 3403? The 3m pads seem too large.

[glen e]

x2 - I have never found this machine to be "light" ....just did my 32 foot boat both hull and inside - which has to be hundreds of sq ft of gelcoat - which is much harder to correct than paint...and the 3403 did it like a champ even with an 8" wool pad 30% of the time...Love this machine...