Difference between wet-sand and heavy compound ?

[cobraa]

Since I never learn how to do wet-sanding, I was wondering if a heavy compound can give the same result as a wet-sand !?

Let say, a wet-sanding will remove 15 microns, with 2 pass of SSR3 I can also remove 15 microns. would the result be the same ? can the correction be the same ? i.e: correcting orange peel.

[Mike Phillips]

In the context of removing orange peel,

Wetsanding with the right backing pad or plate will knock the tops or high points off the orange peel were compounding will tend to remove both the high points and the low points.

Machine compounding generates heat and heat is never a good thing for clear coats even though you'll find people posting that heat is necessary to break diminishing abrasives down this isn't true.

Pressure over time breaks down diminishing abrasives and heat is an unwanted and unnecessary byproduct of the process.

If you want to remove orange peel you first want to make sure you have enough film build to work with because,


Sanding removes paint
Compounding removes paint
Polishing removes paint (to some level)


Here's an article that discusses film build amongst other things...

Wet-sanding - Fresh Paint vs Factory Paint (http://www.detailcity.org/forums/wet-sanding-show-car-results/27775-wet-sanding-fresh-paint-vs-factory-paint.html)


:)

[A4 1.8tqm]

To elaborate on "knocking off the high points" when you wet sand by hand you typically use a sanding block which has a flat surface and will level out the high points quickly. When you compound, the pad will conform to the shape of the surface abrading both high and low points and not leveling the surface. Here's a 50/50 pic of an area I wet sanded by machine, you can see that all the low points were not touched by the sand paper, thus the surface is closer to "level".

Orange peel half removed/orange peel completely removed.

http://i550.photobucket.com/albums/ii437/dave22234/BMW/Pneumatic%20Damp%20sanding/Pneu_DA2.jpg


Closer, half removed

http://i550.photobucket.com/albums/ii437/dave22234/BMW/Pneumatic%20Damp%20sanding/Pneu_DA3.jpg


Closer, Orange peel removed

http://i550.photobucket.com/albums/ii437/dave22234/BMW/Pneumatic%20Damp%20sanding/Pneu_DA5.jpg


50/50 polished out sanding marks.

http://i550.photobucket.com/albums/ii437/dave22234/BMW/IMG_3997.jpg


So no, the results are not the same. Hope this helps

Pics are from my thread http://www.autogeekonline.net/forum/show-n-shine/24493-orange-peel-correction-hand-vs-pnuematic-palm-sander-long-post.html

[Mike Phillips]

To elaborate on "knocking off the high points" when you wet sand by hand you typically use a sanding block which has a flat surface and will level out the high points quickly. When you compound, the pad will conform to the shape of the surface abrading both high and low points and not leveling the surface.


Great explantion...




Here's a 50/50 pic of an area I wet sanded by machine, you can see that all the low points were not touched by the sand paper, thus the surface is closer to "level".

Orange peel half removed/orange peel completely removed.

http://i550.photobucket.com/albums/ii437/dave22234/BMW/Pneumatic%20Damp%20sanding/Pneu_DA2.jpg




Nice photography work, your pictures really drive the points above home...
(no pun intended) :D


:dblthumb2:

[A4 1.8tqm]

Great explantion...

Nice photography work, your pictures really drive the points above home...


:dblthumb2:

Thanks Mike! :urtheman:

[cobraa]

great explanation. thanks.