wet/dry sanding paint before polishing?? HOW DO U KNOW ? ?

[RyansAutoDetail]

ok so i dont have any wet or dry paint sandpaper on me at all and with me just starting out into paint correction land ...

on autopia i see some people dry sanding prodominantly older cars 6 yrs+ using sandpaper disks on the porter cable which i do have..

then they go onto use yellow compounding/cutting pads and a very lengthier process that i never have time to do

im just wondering in most cases i see will this process absolutely be needed even when i have M105 now and smaller 4 inch cutting pads ??

ive seen some amazing work come out of using this first process..

just wondering how many ppl here suggest dry/wet sanding whole vehicles or bad areas and when i should be doing this method prior to correction process.

thanks everyone !

 

[Beemerboy]

Sanding on a cars finish is for extreme measures and anyone using there orbital on the surface for sanding of a car is asking for trouble.

Sanding in general is for correction purposes meaning much more than swrils from washing or tunnel washes or the likes of that...mainly I use it for scrtaches that are just into the clear or when I fill a rock chip.

If you have the experience with a rotary and the right pad and product combo, you can correct about any paint without sanding.

I would add that its hard to tell when sanding is needed but I would say that its less than 5% of the time....in the years that I have worked on cars I can say that I've wet sanded very very little

 

[RyansAutoDetail]

Sanding on a cars finish is for extreme measures and anyone using there orbital on the surface for sanding of a car is asking for trouble.

Sanding in general is for correction purposes meaning much more than swrils from washing or tunnel washes or the likes of that...mainly I use it for scrtaches that are just into the clear or when I fill a rock chip.

If you have the experience with a rotary and the right pad and product combo, you can correct about any paint without sanding.

I would add that its hard to tell when sanding is needed but I would say that its less than 5% of the time....in the years that I have worked on cars I can say that I've wet sanded very very little

yah thats what ive figured but i see some outstanding results by sanding the paint prior to polishing so i dont know really why when there are very good methods that dont require this step ...

lets hope i dont get any of that 5% of cars that cant be fixed with the things i have

thanks !

 

[MrCLRider]

I believe that there is one guy on the Meguiars Forums that is starting to sand alot, and he had a good point about with the proper technique, and supplies, that you could inflict less damage to the paint instead of going the three step route and doing a heavy compound, then light compound, then final polish...I thought he was making a good point.

 

[JaredPointer]

Body shop guys use sand paper on DA's all the time. I was told it is actually easier to remove the DA sanding marks than it is straight line wetsanding marks by hand.

 

[black bart]

Body shop guys use sand paper on DA's all the time. I was told it is actually easier to remove the DA sanding marks than it is straight line wetsanding marks by hand.

I have a good friend that has worked in a body shop for 35 years he uses a air sander with 3000 dry on new paint.

I think it is done because it is much faster than doing it by hand.
I would not recommend this to a beginner especially on a factory paint job.

Wet sanding is done all the time on custom paint to make it more level but caution must be used on factory paint it is thin.

I have wet sanded the factory paint on my Ranger pickup but I would not do it to someone else's car because I would not want to take the chance of paying for a repaint.

 

[Poorboy]

Body shop guys use sand paper on DA's all the time. I was told it is actually easier to remove the DA sanding marks than it is straight line wet sanding marks by hand.

that really depends on the panel being worked on ... flat surfaces are easier, but curved areas and edges are best off done by hand

 

[black bart]

that really depends on the panel being worked on ... flat surfaces are easier, but curved areas and edges are best off done by had

TRUE but to those who are new to this when you read sanding by hand that don't mean holding the sand paper in your hand you want to use a rubber sanding block and if you are working a curved surface use a flexible block to prevent your finger from applying more pressure at that spot.
These rubber sanding block can be found at a auto paint store.

 

[RaskyR1]

The only time I wet sand a car is when I'm trying to remove orange peel from a car that has been repainted. Even then I will only do so if I know the car has an adequate amount of clear/paint to do so. On a very rare occasion I may feather sand an isolated scratch on a car with OEM paint.

As far as what means you use for sanding, DA is the way to go when you have nice flat areas. Though I recently wet sanded a '66 Vette that had to be done by hand because of the amount of curves.

FYI, a DA like the PC is not the same as the DA's used at body shops either. The PC has a much larger throw and I would not suggest using it for wet sanding.


I honestly cannot recall the last time I had to wet sanded on a car with factory paint. :hmmm:


Rasky

 

[sfu7274456]

I think that sometimes wet sanding is the way to go. Recent example is the wifes mustang that I just did, I tried everything I could and although I was removing the scratches with 105 and the rotary, it was taking forever. I finally gave in and wet sanded it with progressively finer grits until 2000 grit, then followed up with the Flex and 105. The sanding scratches came out easier than the original scratches that I started with. Just take your time and go slow, it is nerve racking at first but after A while you get the hang of it.

Before:

After:

 

[RaskyR1]

I think that sometimes wet sanding is the way to go. Recent example is the wifes mustang that I just did, I tried everything I could and although I was removing the scratches with 105 and the rotary, it was taking forever. I finally gave in and wet sanded it with progressively finer grits until 2000 grit, then followed up with the Flex and 105. The sanding scratches came out easier than the original scratches that I started with. Just take your time and go slow, it is nerve racking at first but after A while you get the hang of it.

Before:

After:

Did you use a PTG to measure how much material you removed?

You likely removed .2-.3 mils by doing your above process. No doubt sanding is a fast and easy way to take out deep scratches, and your end results are going to look better, but now you have left yourself very little material on the car for future corrections.

When working on OEM paint you have to decide how far you really want to go considering you only have .3-.5 mils that can safely be removed. In your case this was your wifes car, but on a customers car is it really the best solution? If I can't remove some deeper scratches after a few passes with a wool pad, and an aggressive compound like M105 on the rotary, I'm likely going to tell the customer they should just leave them alone. :howdy

Cheers, :cheers:
Rasky

 

[sfu7274456]

Negative I did not use a PTG, and if this was a customers car I would have probably left it alone.