Damp-Sanding Advice?

[Mary Steinborn]

Hi, I am too far away to attend your Show Car Garage, and I know you did one on damp sanding.

Can you point me in the direction of any videos or articles on this subject as guidelines for how to do it correctly?

Thanks!

[Mike Phillips]

Since this is your first post to our forum...

Welcome to Meguiar's Online!

Hi, I am too far away to attend your Show Car Garage, and I know you did one on damp sanding.

Can you point me in the direction of any videos or articles on this subject as guidelines for how to do it correctly?

Thanks!

What are you working on?

[LuxuryMobile]

Meguiars Online???

[Mike Phillips]

Meguiars Online???

I actually have a few articles on sanding on MOL and over here.

I'm working on finishing an article right now that I started previously and will post in the next few hours.

[Mike Phillips]

Can you point me in the direction of any videos or articles on this subject as guidelines for how to do it correctly?

Thanks!

We shot a video on damp-sanding but it hasn't made it to editing yet. I can ask Yancy when he can get to it tomorrow.

I have two articles on damp-sanding, one is quite lengthy and almost done and I have the short version almost done and will post it by end of day.

Here's some articles on the topic of sanding paint in general and there is some important information that relates to the process of sanding no matter which method you use.

List of Sanding Discs at Autogeek.net
The Rule of Thumb
If it has paint... it gets polished...
RIDS and Feathersanding - A Highly Specialized Technique by Mike Phillips
Wet-sanding - Fresh Paint vs Factory Paint
Basic Hand Sanding Techniques
Removing Orange Peel & Sanding Marks with the Griot's ROP and the Wolfgang Twins
How long will a half sheet of wet/dry sandpaper last before it stops cutting and you need to replace it?
Fight or Flight Method for Gaging Surface Temperature


Remember, sanding is easy... that's putting scratches into the paint... it's getting them 100% out that's kind of tricky.

In the refinishing world, the sanding is done on fresh paint which will buff easier and will be thicker than an original factory finish. An original factory finish will be fully dried, cured and set-up and will trend towards being thinner and harder than a custom paint job.


Here's an article that talks about modern clear coats and paint hardness...

The practical differences between single stage paints and a clear coat paints

[Mary Steinborn]

Since this is your first post to our forum...

Welcome to Meguiar's Online!





What are you working on?

Thank you, Mike!

The application is a factory clear coat on a 1997 Ford Explorer that hasn't had anything done to it yet, other than washing and waxing.

I am wanting to reduce the factory orange peel, even if not to completely eliminate it. I know the cautions there. I am actually thinking of going right to 3000 and 4000.

And I have a rotary that I am fairly comfortable with for removing the sanding marks.

I also have a hood I practice with; I will probably do the process there first.

And yes, I usually post on MOL.

Thanks for the pointers to the articles. For the things you have in the works, I will wait patiently for I haven't ordered the sanding discs yet.

Thanks again!

Mary

[Mike Phillips]

Thanks for the pointers to the articles. For the things you have in the works, I will wait patiently for I haven't ordered the sanding discs yet.

Thanks again!

Mary

Hi Mary,

I have to take a couple of updated pictures and then I'll post it, hang tight...

[Lasthope05]

Thank you, Mike!

The application is a factory clear coat on a 1997 Ford Explorer that hasn't had anything done to it yet, other than washing and waxing.

I am wanting to reduce the factory orange peel, even if not to completely eliminate it. I know the cautions there. I am actually thinking of going right to 3000 and 4000.

And I have a rotary that I am fairly comfortable with for removing the sanding marks.

I also have a hood I practice with; I will probably do the process there first.

And yes, I usually post on MOL.

Thanks for the pointers to the articles. For the things you have in the works, I will wait patiently for I haven't ordered the sanding discs yet.

Thanks again!

Mary

It is not recommened to sand factory paint because it is already thin to begin with. With sanding you will weaken/reduce its ability to block UV rays which will lead to clear coat failure in the future.

Also 3000 and 4000 grit will not work effectively at removing orange peel. Those are finishing disks to refine your previous sanding scratches. Also the 3000 and 4000 grit disk are either a foam backing or a soft abrasive cloth which when pressure is applied will conform to the orange peel and will remove paint from both the highs and lows of the paint.

[Mary Steinborn]

It is not recommened to sand factory paint because it is already thin to begin with. With sanding you will weaken/reduce its ability to block UV rays which will lead to clear coat failure in the future.

Also 3000 and 4000 grit will not work effectively at removing orange peel. Those are finishing disks to refine your previous sanding scratches. Also the 3000 and 4000 grit disk are either a foam backing or a soft abrasive cloth which when pressure is applied will conform to the orange peel and will remove paint from both the highs and lows of the paint.

Alan, I will be sure to stay within the safety margins. I have found even compounding in a test spot made the orange peel better. I realize full removal is probably not wise. I just want to do the best I can the first time around. I will be happy with just a little bit of leveling. I have a testing used hood with orange peel too, and I will test things out there first. But the integrity of the clear coat is of primary importance.

[Mike Phillips]

It is not recommened to sand factory paint because it is already thin to begin with. With sanding you will weaken/reduce its ability to block UV rays which will lead to clear coat failure in the future.

Good points for anyone thinking about sanding a factory finish. I spoke with a consultant to the car manufacturing industry about this very topic about 3 weeks ago and he said a minimum of 1.3 mils is needed to prevent failure of the basecoat. I've always been told and he confirmed that new cars get 2.0 mils of clear at the factory, so there's a little wiggle room. The bad part is that in the future there's not much film-build left for removing future swirls, scratches, etchings or other below surface defects.

Also 3000 and 4000 grit will not work effectively at removing orange peel. Those are finishing disks to refine your previous sanding scratches. Also the 3000 and 4000 grit disk are either a foam backing or a soft abrasive cloth which when pressure is applied will conform to the orange peel and will remove paint from both the highs and lows of the paint.

While that's true, for what it's worth, what I've seen for the last 3 cars that I've sanded down with these Meguiar's Unigrit discs is that you do decrease orange peel even when sanding with foam backed finishing discs. Except for the rental car at this year's Mobil Tech Expo everything I've been sanding has had a custom paint job, i.e., more paint and some level of orange peel.

We sanded the hood of this car 3 times at the 2010 Mobil Tech Expo and then a few random places on the hood and the trunk lid throughout the 3-day event.





The foam backing is pretty thin and you can use them without the foam interface for a more aggressive cut like for removing surface texture, here's a few pictures to give you and idea of how thick or actually how thin the foam backing really is...

1500 Unigrit Sanding Disc


1500 Unigrit Foam Finishing Discs


3000 Unigrit Foam Finishing Discs



There's also a foam interface pad which is just under a 1/2 inch thick and this will reduce the aggressiveness resulting in about a grade shift upward in cut. For a more aggressive cut, don't use the foam interface.