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ok i just signed up for this board because i have some questions. ive been following this for some time and just started to paint a hood as a test piece. im using rustoleum gloss black, and am thinning it down with mineral spirits about 30%. it seems to have a slightly more watery milky consitancy. anyways i prepped my hood with 320, then painted, and im doing thin coats. after two coats i sand with 600, and so far i have... coat 1, coat 2, sand 600, coat 3 coat 4, sand 600, coat 5....coat 5 is drying but i can see the 600 grit scratches. am i doing something wrong. im assuming im thinning the paint too much, either that or putting it on too lightly. what do you guys think? although the paint seems to be rock hard after about 7 hours of dry time, in 50 degree weather...



I think you are following the recipe for success properly...

Are you 'sanding' between second coats or 'wet sanding' between second coats ?

From the sounds of the 600 grit scratches it almost sounds like you are dry sanding ? If it is not a dry sanding problem... then maybe you are putting a little too much elbow grease into the 'wet sanding' ?

What type of sandpaper are you using ? In the 600 range I found the Norton's 3X sandpaper to be nicely agressive and long lasting. The 3M 600 grit is fairly decent for wet sanding.

If all else fails you might step things up to the 800 or 1000 grit for wet sanding. It is sufficiently agressive to remove any high spots and is fine enough grit that it should not leave any outrageous scratch marks ( nothing that the later 1500 and 2000 grit can't remove ).

In theory the thin layers you are adding should be able to fill in a 600 grit scratch.

IF at this moment you are looking at a body panel that bears 600 grit scratches you have one of two ways to go about getting things back on an even keel...

a ) take a 1000 grit sand paper and level the entire surface down to where the 600 grit scratches are no longer an issue. Then add your next two layers as usual.... followed by the wet sanding with the 1000 grit... or

b ) You could go ahead and lay three coats onto the 600 scratched surface. Hopefully the first coat would fill in the 600 grit scratches. By the second coat the 600 grit scratches should be history. And with the third coat your 1000 grit wet sanding should be able to level any high points that happened during this 3 coat stage.

My personal preference would be option B - as it takes you ahead three coats... whereas the option A takes you back one or two coats.

Hope this helps.

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Last edited by Marq; 09/24/06 09:34 PM.