Paint

I have a greay XJ with clear coat... I was thinking about spraying it primer black than throwing a couple coats of royal blue on that with a clear coat... My question is, do I need to sand the clear coat off? Is a black primer going to show the blue better or should I got with grey? If I dont not add the clear coat after I paint it, how long can I expect the rust to stay away before I need to repaint?

MOOSE16285 said:

I have a greay XJ with clear coat... I was thinking about spraying it primer black than throwing a couple coats of royal blue on that with a clear coat... My question is, do I need to sand the clear coat off? Is a black primer going to show the blue better or should I got with grey? If I dont not add the clear coat after I paint it, how long can I expect the rust to stay away before I need to repaint?

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Really clear is nothing other than paint with no pigment, so as long as you go over the old paint with wax & grease remover and sand it good enough to rough it up a little, the new paint will adhere fine. You don’t have to sand it all off, and you are better not sanding to bare metal if you don’t have to. If you hit the metal you remove any rust preventative coatings that may be there. Make sure to wet sand it or the sand scratches will show through, though.

With the new paint you can use a color that is designed to be a top coat, and it will be glossy and seal the finish fine. This is what all cars got before they started clearing everything at the factory, and it is fine to use. Or you can get a base coat/clear coat system. With the base/clear the base color coat dries really dull and you get your gloss from the clear. So it depends on what kind of paint you buy, talk to the guy at the paint store. I’d use either PPG’s Deltron Polyurethane (unless they’ve changed the name in the last few years) or to save money their acrylic enamel. On older colors that are not available in base/clear I have used lacquer as the base and then given it a coat of urethane clear to get the durability. How long the rust stays away depends on how good of a job you do with the prep work. If you leave any rust under the new paint it will pop back through very quickly.

As far as primer color, you should use a dark primer for dark colors and light primer for light colors, mainly so dings and chips don’t show up as much. If you go too light on the paint coat it will look splotchy no matter what primer it is.

Your paint jobber should tell you that modern paints with hardeners are extremely hazardous. Be very careful about wearing a filter while mixing and sparying these paints, better yet is a fresh air system. There is a very good discussion group on auto painting at http://www.autobodystore.com/cgi-bin/config.pl?index

Truk said:

Really clear is nothing other than paint with no pigment, so as long as you go over the old paint with wax & grease remover and sand it good enough to rough it up a little, the new paint will adhere fine. .

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That is not true. Clear is HARDLY anything but paint w/o pigment. Clear has certain additives that allow it to resist the elements better tahn regular paint. Sure that is an extremly elementary description of clear but it isnt all true. But you are correct in that if you rough it up enough to not show any shine whatsoever after cleaning it with a W/G remover it will be fine to paint over. As for the question about how long paint will last w/o clear. Not long if you live up north. Down here in LA it last about 2 or three seasons before a lot of surface rust bulids up. I would suggest just going with a single stage paint (clear and paint mixed together) then just wet sand and buff it to get a really nice shine and no orange peel. Also if you cant get a blue primer it would be fine to mix some of the same colored blue dual stage paint in with a more common grey primer.

Primers suck up moisture, use old school flat black if thats what you want. As far as the clear coat, the problem is it delaminates, spray over it and it will just delaminate and take the black off from underneath. Sand it down, yea, will take a few hours but it's worth it, then prime, then paint...

Before you do anything wash it aggressivly with a high detergent soap like Dawn or Tide. Then hit is with a good wax and grease remover. Start sanding on your current paint with some 240 and then 400 both wet on a long board. Use a good epoxy primer to ensure good adhesion. Spray your sealer and move on to color. In your case I would probably go with a single stage paint. You don't have to clear it and its one less step. If you are going to use a base coat clear coat system you really have to shoot the clear. Since base coat is a physical drying paint, any solvent that you spill on the paint will turn it back into a liquid. Even a small drip of gas will do this. Clear coat is a chemical drying paint that can't be turned back into a liquid once it cures.