I'm just getting my feet wet with my new DA sander and an assortment of stick-on discs. I've been lurking here and on autobodystore.com and appreciate all the good info.

Searched the archives, but couldn't find a "basics of sandpaper" -- I'm looking for a quick description of what grits to use in what situations, start to finish.

Right now, I'm scuffing and smoothing my faded original paint. For the time being, I'll cover it with MS5121 (black) epoxy primer, until I get some more experience, time, and money to finish the job right.

I started wet sanding with 180 grit, and wonder if that's OK to shoot primer over, or if I need 220 or 320 to avoid scratches showing through?

Many thanks,
mark.
'71 Fodor

Sorry, I have not done a "Basics of Basics" on sandpaper but I have sure planned on it.

Epoxy doesn't fill that well and 180 is on the edge. I would say go up to 220. But the thing is, if you NEED the 180, you NEED 180. In that case you need to change to a urethane primer or plan on working with finer paper once the epoxy is sprayed to remove the 180 scratches. The 5121 will probably fill the 180 ok, but it nice not to rely on the primer to do a whole lot of filling.

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1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
"Fan of most anything that moves human beings"

Thanx for the quick reply. To be honest, I don't know whether I needed the 180 or not. Out of ignorance, I just grabbed that first. I'll hit it again with 220 before I prime... And I'll keep an eye out for your "basics of paper".

How would I know if I "need" 180, or would be ok starting with 220? The original paint is pretty well oxidized (ugly), but seems well adhered. I'm not stripping it all, just trying to get a good surface to prime over. The wet 180 took away the faded/oxidized layer in a hurry. And of course, being new to the world of DA sanding, I cut right through to bare metal at the edges. Learning through experience...

Thanks again for your help,
mark.
'71 Fodor

You would need the 180 if you had to take off a lot. You have to choose the grit that will do the most cutting you can, but not be coarser than the next step can take. That is the basic trick to sand paper choice. Now it is easier said than done, and that is why I need to do a "Basics" on it. http://www.chevelles.com/forum/smile.gif

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1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
"Fan of most anything that moves human beings"