To Wetsand or to Compound?

[Denzil]

So I'm thinking of purchasing some Meguiar's Unigrit wet sandpaper (probably 1500, 2000, 2500, and 3000) sometime over the summer just in case I come across some really bad cars.

So what paint conditions determine whether to use wet sandpaper or to use compound on a vehicle? I'm not sure what determining factors I should be looking for to determine what approach I should be using. If someone could enlighten me about this from their experiences and possibly post pictures of when to wet sand and when to compound, I'd definitely appreciate it.

Thanks!

[salty]

For me i use 2000 to sand deep scratches, even if they are too deep to remove.

If i am being paid for a 2 or 3 step i will usually go around the car and sand the deep scratches and scuffs and then compound as usual.

I rarely get paid for full panel or whole car sanding.

[themightytimmah]

^ what he said. I would only recommend full panel or full car sanding if you have an air d/a setup, a thickness gauge, and are willing to charge big bucks.

I usually wetsand deep scratches with 2000 or 3000, and I sand any touchup blobs that the owner or previous owners may have left behind. Other then that, it's all compound. I've only done whole panel sands on a few occasions, and those were to correct orange peel from poor repaint work.

[Denzil]

Interesting... so it seems that it's subjective? I'm still quite confused if it really is subjective or if there are definite things I should be looking for that would require me to wet sand, more specifically, spot wet sand.

I guess I'm just trying to avoid wet sanding if it's possible but I'm just having a hard time understanding where wet sanding is appropriate.

[salty]

Personally i would rather wet sand a defect that grind away with the rotary and compound.
It's faster and safer and does a better job.

[salty]

A couple examples of where wet sanding is needed.

A before and after of some dog scratches.





Box scratch plus a little paint touch up

[charlesaferg]

Originally Posted by themightytimmah

^ what he said. I would only recommend full panel or full car sanding if you have an air d/a setup, a thickness gauge, and are willing to charge big bucks.

I usually wetsand deep scratches with 2000 or 3000, and I sand any touchup blobs that the owner or previous owners may have left behind. Other then that, it's all compound. I've only done whole panel sands on a few occasions, and those were to correct orange peel from poor repaint work.

Ooo, I'm giddy like a schoolgirl.
A dual action air setup? Tell me more.
Old school.

[phamkl]

Does it got to be pneumatic? I got a UDM and a friend with some messed up paint. I was planning on getting some wet sand pads and get some experience machine wet sanding.

[Denzil]

Thank you for the examples salty! That should give me a good idea of when to wet sand.

If anyone could, please provide more wet-sand situation pictures!

[themightytimmah]

Originally Posted by phamkl

Does it got to be pneumatic? I got a UDM and a friend with some messed up paint. I was planning on getting some wet sand pads and get some experience machine wet sanding.

It doesn't have to be an air sander, but the length of throw is key. The UDM has too long of a throw, so it'll cut too fast and make little squiggly marks that are nearly impossible to remove.

3M makes an excellent air sander, they even have a pretty cool kit that fits in a box. You can 3000 grit a whole car pretty quickly and it really brings out the paint if there is enough thickness left to sand.

[Accumulator]

Even though my good painter tells me to use 1500 now and then, *I* recommend that people stick with 2-3K grit, at least until they get a very good feel for this stuff. And yeah, no way I'd be doing this on somebody else's vehicle without a thickness gauge.

[danponjican]

Good read on wet sanding...

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