Not understanding the differences in sanding methods.

[jta98z]

Hey guys. Happy Thanksgiving. I was reading something the other day that said dry sanding was meant for factory paint while wet sanding was meant for repaints. I'm fairly confident I've seen guys wet sand factory paint. Can you guys substantiate this claim?

[hernandez.art13]

Why were they sanding factory paint? (Just wondering)

[hamlyn]

I don't believe he is asking about sanding fresh from the factory paint. In general, is one type of sanding reserved for one type of paint, while the other for another?
Is wet-sand strictly for paint-shop/body shop paints?

One scenario I can think of to sand factory paint is to level orange peel.

[Harry Da Hamster]

Dry sanding factory paint... or any paint? Ouch!

[rescuenut10]

If I hand sand, I go with a wet system, If I use a da, I use a dry system with a interface pad.

[jdbillin]

If I hand sand, I go with a wet system, If I use a da, I use a dry system with a interface pad.

Using a da is awesome to knock all the orange peel down flat. I used to do it all by hand until I discovered the da. I wish I would of bought one years ago

[rescuenut10]

When I do da sanding, I try to blow off the surface and sand paper regularly to avoid build up scratching the surface.

[Calendyr]

I don't think dry sanding is that bad. Renny Doyle teaches dry sanding in his course. I believe Mike Philipps also put out a video recently where he was dry sanding a car.

Wet sanding is more efficient because it prevents the paper from clogging.

[jta98z]

I don't believe he is asking about sanding fresh from the factory paint. In general, is one type of sanding reserved for one type of paint, while the other for another?
Is wet-sand strictly for paint-shop/body shop paints?

One scenario I can think of to sand factory paint is to level orange peel.

Right. That was the gist of my question. I hadn't heard of anyone dry sanding paint and didn't know why it was specific to different paints.

[Mike Phillips]

There are benefits to both dry and wet, sometimes it comes down to personal preference.

If you dry sand though you should wear a air filter mask so you don't breath saned paint particle into your lungs. This is why I normally wetsand as the paint particles are trapped in your water slurry with less chance of becoming airborne.

Dry sanding makes checking the level of peel removed faster as you don't have to wipe away water and wait for any water film to flash evaporate before you can see the peel/no peel difference. Like this,

Dry Sanding Results





The new flexible 3M Hookit sheets are made using some type of no-loading technology, it seems to work pretty well.


Here's a few recent threads on this topic with pictures to boot...

Dry Sanding & Wet Sanding with 3M's Flexible Abrasive Hookit Sheets

Here you go... pictures showing the sanding sheet being cleaned using terrycloth...



Here you can see the single stage yellow paint on the face of the Hookit sheet.




A quick wipe with a clean, terry cloth towel and the paint residue wipes almost completely off. You can use compressed air too...






Here's another with some great pictures...

Removing #1500 Sanding Marks with Rupes Bigfoot 21 Polisher


Now I've zoomed in and you can see the orange peel on the right side where I did not sand and how the paint starts to flatten out as you look to the right side of the picture.





And another article with pictures of both dry sanding and machine wetsanding...


Pictures: 1928 Model A - Wetsand, Cut and Buff at Autogeek



Den wetsanding the curve of the roof...
It's always great to have Den here to help with these projects. Sometime in the near future we're going to have Den's GTO here for a show car makeover.