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could you give me some ideas on what grits to
use for the prep process on my car ?? as i have not got a clear coat on the original paint
i dont know whether to start with a higher grit
than 80 /120 like most people did here

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I am pretty sure I would stay away from an 80 grit for sure. A 120 would work out nicely and even a 180. Sometimes it depends on the sandpaper itself.

One of the sandpapers I was using was the next nearest thing to useless on the paint. It either would not sand anything off or it would clog up with whatever particles it was able to sand off.

My best luck came with one of the 3m papers that I bought at Home Depot. But before coming to that conclusion I had gone through a couple of sheets of crappier sand paper.

The key thing to think about with the sandpaper is you don't want it to be scoring up the body panel surface too much. Some of the grits can really cut quite a good scar into the original paint ( or even the later coats of paint that you apply ).

Since the paint is being put on in such thin layers, it may happen that a badly scarred surface will not find the scratches ( or the low area of the scratch filled in fully with each coat of paint.

As we had discussed previously in this thread, when you add a layer of paint to a scarred surface, equal amounts usually end up deposited in the valley of the scratch and on the peak of the scratch. So the original scratched surface ends up not really being leveled out. That is why we use the increasing grit size of the sand paper during the process to lessen and lessen the size of any scratches created by the previously used lower grit of sand paper.

So you may have to experiment with the different brands of sandpaper out there to find the one that does the best job for you, with the least scratching and clogging.

I seem to recall that my favorite 3m sand paper was an aluminized type sandpaper and there was actually a patter in the paper so that the sanded off artifacts could be channeled out of the sand paper so that it didn't clog up while sanding.

When I moved on to wet sanding, I went with the 3m wetsanding paper ( which is pretty universally available ) and is manufactured on a cloth like material that can handle repeated wettings without falling apart.

Dunno if this helps...

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