Does Wetsanding = Clear Coat Failure

[SR77]

Can Wet sanding and then compounding with a rotary be done without Clear Coat failure in the future. I have read alot about clear coat thinkness threads on here and the fact that you aren't suppose to remove any where from .3 to .5 mils or there will be clear coat failure in the future. I am going to try and restore the front end of my sisters car which has some touch up spots that need to be wet sanded down and the hood has some pretty bad water spot etching. I am asking because I am not sure if wet sanding and compounding once will remove to much clear coat, but also because she plans on keeping the car for a long time and I not only want to resore the shine on the front end without a clear coat failure down the road, but i also want to be able to clean and polish the paint to keep it maintained too in future details. So, can wetsanding and compounding be done without the risk of clear coat failure and will i still have enough clear coat left for future cleaning and polishing of swirl marks down the road? Also, What does Clear Coat failure that everyone talks about on here look like? thanks for the help.

[tguil]

It takes talent to wetsand properly. You are quite likely to make a bigger mess than you already have. If you know how to use a rotary buffer I think that you should just use the buffer and call it good enough.

Tom

[jfelbab]

I'd never wet-sand without checking the thickness first. Beg, borrow or rent a thickness gauge.

Do you know the history of the finish? Factory CC are pretty thin. If the car has been repainted you probably have much more thickness to work with.

How much experience do you have with wet-sanding? How much are you prepared to spend if it gets mucked up?

I remember someone posting a pretty good example of clear-coat failure but I can't locate it now. It is ugly, much uglier than scratches.

Edited to add:

I found it. If you look around at a few older cars you can find some that look like this or worse. Once this starts it spreads quickly and the basepaint under CC is pretty soft and oxidizes quickly.

[Mike Phillips]

Just to add on to what everyone else has written,

All of the UV protection for a basecoat/clear coat paint system is in the clear coat. So keep that in mind.

The environment in which you live, drive, and park your car in will also have an effect, basically if your car's finish is exposed to the sun all of the time, this will be a factor to consider.

Out here in Apple Valley where I live, as I drive around or walk through parking lots, I see a lot of cars with utter, complete clear coat failure on the horizontal surfaces, as well as cars the same make and year that have intact finishes.

So I know the sun out here in the High California Desert has an effect on longevity, but I have to wonder if the older cars that the clear coat hasn't failed, have been parked in a garage when not in use.

Just this week I noticed all of the water in the battery in my 1973 Blazer was gone, bone dry. Coming from Oregon, we check the water level in our car's battery occasionally, but it's not a major issue. Up here in the high desert, it's often around 100 degrees and things dry up. The battery is 1 year old, a major name brand and just being parked outside all of the time, the ambient heat evaporated all of the water out of the battery over time.

I've also noticed the gas in our lawn mower has a tendency to evaporate out because we don't have a large lawn, but the tank appears to be empty often.

Taking exposure into consideration when deciding whether to wet-sand or not, the one thing I always say is this,

"Sometimes you're better off to improve a defect in your car's finish than to try to completely remove the defect".

The life of your car's paint is in part, in the film-build, or thickness.

Hope this helps...

Mike

[Beercan31]

This is the best pic. I can find that shows clear coat failure.

I am going to try and restore the front end of my sisters car which has some touch up spots that need to be wet sanded down.

Are these stone bruise repairs? or bigger?
If these are stone bruise repairs you would be fine with a "very" small spot repair, if they are larger it would be a good idea to have some practice on a junk yard door, hood or trunk. Take in mind like Mike said:
The environment in which you live, drive, and park your car in will also have an effect, basically if your car's finish is exposed to the sun all of the time, this will be a factor to consider.
and also jfelbab:
Do you know the history of the finish? Factory CC are pretty thin. If the car has been repainted you probably have much more thickness to work with.


IMHO
any time you minimize the clear of any veh. you are taking a chance that clear coat failure will occur at some point down the road.

[Ghettocivic]

Here is a good picture of clear coat failure. This is my car its a 93 and has been parked outside all its life

Roof
[/IMG]

Trunk


Close up

[jfelbab]

My deepest sympathy.

That's about the worst I've seen.

[Beercan31]

jfelbab said

That's about the worst I've seen.

I concur

Ghettocivic Dude the next time your hear someone say "Do You have it Bad" you might want to jump up and say "YES I DO"

[SR77]

thanks for all the replys. Considering that i don't have a paint thickness gauge, I will probably just polish and live with some of the damage. I just read alot about others wetsanding their finish and don't see why they would if it is most likely going to lead to damage down the road. All of these seminars that meguiars offers always teaches wet sanding and while it was very interesting to learn i wonder why they teach wetsanding to remove paint defects if there is a good chance it will remove to much clear coat.

[rjstaaf]

It is a valuable skill to learn. Just like any tool you have to know the appropriate time to use it.

You would certainly want to think twice about doing any wet sanding on a car that is driven daily as it will constantly be exposed to UV and the thinner clear will not protect as well.

What about a car that is not driven regulary, maybe a show car with a very expensive paint job. Wet sanding might be just the answer to repair a defect rather than pay for a very expensive repaint. Since the car is not regulary exposed to the elements clear coat failure is not as much of a worry.

Just my 2 cents