Sanding clear coat

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bartigue
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Sanding clear coat

Post by bartigue » Fri Feb 16, 2018 6:03 pm

The 82 has a great deal of marring on the clear coat from living under a cover for years. I tried polishes in the orbital but can’t quite get down to the marks. These are all over the clear. I’ve heard of folks sanding clear coat using a fine sandpaper - 200 or 400 - and slowly working up to ultra fine before using machine polishes.

Anyone done this? It seems to me similar to color sanding except to the clear.
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Brad Artigue
1982 Spider 2000
I've restored, worked on, sold, bartered, and bled for:
1970, 1979, 1980, 1981, 1982 124 Spiders -- 1969, 1970 850 Spiders -- 77 X1/9
http://fiat.artigue.com
Spidernut79
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Re: Sanding clear coat

Post by Spidernut79 » Sat Feb 17, 2018 1:11 am

DO NOT USE 200 or 400 - you will have no paint left.

I've restored the finish to several cars including clear coats. Given what you explained regarding the scratches from the car cover, I'd recommend Maguiars Scratch X. Try it on a small and inconspicuous area. If it doesn't take care of it by hand, you can use a foam buffing pad at a very slow RPM and lots of movement so you don't burn the paint or burn through the paint. Again, go slow! An alternate product is Turtle Wax Scratch and Swirl Remover. Both are good and I've had outstanding results removing light scratches and damage to the clear coat surface.

If that doesn't remove the scratches, you can use 2000 grit wet or dry sandpaper with lots of flowing water to wash away any dirt, old clear coat or contaminants. You'll then have to go back and buff it back out with a product like Maguiars Scratch X or Turtle Wax Scratch and Swirl Remover. Again, you could use a foam pad and a buffer on a very slow speed and lots of movement. You can then buff out the car with wax.

The older the clear, the harder the clear will be to buff back to a really nice shine. I do not recommend anything harsher than 2000 grit wet or dry sandpaper no matter how bad it is. Anything rougher will leave deep and hard to remove scratches. The key is to take it slow. Clear coat is pretty thin and it is easy to cut right through it.

If you're really brave and neither of these techniques work, you can scuff the surface well with 600 grit wet or dry sandpaper being careful not to cut all the way through the clear coat. You can then respray the clear using SprayMax 2K clear in an aerosol can. I did my son's rear door and my daughter's hood, roof and trunk. Both look as good as the original finish. It is a two-part catalyst clear just like the factory finish. The spray nozzles are outstanding and with any skill at all, you can lay a perfectly flat and high gloss clear that will last for years. It takes about one can to do a Fiat hood.

John
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bartigue
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Re: Sanding clear coat

Post by bartigue » Sat Feb 17, 2018 7:32 am

I'l try the Scratch X first. I used a Griot's machine polish (#4) on it but it was too fine to do anything more than remove the most basic scratches. I am out of, and apparently they no longer make, the numbered polishes. I can't figure out the new polishes at Griot's and I'm too lazy to try to learn, I think they just rebottled the old stuff and added $10 to the cost per bottle.
-----------------------------------------------------------
Brad Artigue
1982 Spider 2000
I've restored, worked on, sold, bartered, and bled for:
1970, 1979, 1980, 1981, 1982 124 Spiders -- 1969, 1970 850 Spiders -- 77 X1/9
http://fiat.artigue.com
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mikehynes
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Re: Sanding clear coat

Post by mikehynes » Sat Feb 17, 2018 12:58 pm

An automotive paint store should be able to provide everything you need. And if they are any good also give you advice. It might be possible to sand out the scratches with 2000 grit wet/dry paper but be very careful. Once you sand through that layer of paint - well - it's gone.
Most good quality paint jobs will be wet sanded and polished as a finishing touch, so it's SOP and works just fine. But, if the painter knows he's going to wet sand, he might apply the clear a bit thicker. If the scratches are really just from a cover you should be OK, just stay away from the high spots.
Two '80 124 Spiders
Lots of X1/9s
Mike Hynes
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