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Repairing Paint Blemishes

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Subject:       [RAM] Fixing that "First Blemish"
From:          CSiano@banyan.com

> I've tried touch up paint, but know I'm eventually going
> to have to break down and get the whole thing painted.

One of the reasons I bought a white truck was due to the fact that the white is much stronger paint than any of the colors.  White also hides scratches very well.  However, I did have a Blue Dakota, so i know some of the scratch woes everyone is having.

I had two major scratch problems that I took care of myself, and had great results.  This process should work on most colors, but the darker the color,  the less perfect it will come out.  Black is the worst, but if you are willing to spend the time to sand carefully and polish by hand, you can get near perfect results.  My first major area was a very badly scratched rocker panel where I had dragged the truck on a dirt berm while off-road.  The second was caused by a bicycle pedal rubbing on the tailgate while I carried it on a hitch mounted bike rack.  Both areas were large collections of multiple scratches.

First, use some sandpaper and lightly wet sand the area to remove wax, crud and to scuff up the paint.  I use a 400 grit for this as it won't remove a lot of the original paint, but does rough it up quickly enough.  I did a fairly large area making sure to go lightest the further I was from the blemish.  It is OK to sand down to primer, but if you go to bare metal, you'll have to sand out the areas a bit and re-prime.  Use the same method I describe below to apply the primer.  The only difference is that you want REALLY light coats, and it only takes a few minutes to dry between coats.  Cover the metal, but the blend into the paint can be light enough to see the color behind the primer.  Don't put too much on.

Clean the sanding area up with water and towel dry.  The surface has to be totally dry and clean.  The prep is 80% of the finished look, so any imperfection here is going to be very visible later.  Run your hand over the surface.  If you feel something, sand it down.  If there is gouging in the metal, you can use a little body filler, but it is probably better to shoot with primer and sand down.  With body filler, you need clean metal to hold properly,  This is tough on small nicks.  If you are doing a large area, then take the time to bring it down to bare metal and fill.  If you need more than 1/8" thick of filler, try to hammer out the dent.  This starting to get more advanced, so I'll leave the filler and dent removal to another topic.

I taped large sheets of paper (newspaper actually) as a mask around the area.  I left a lot of space so I could blend.  the mask protects the windows, lights, tires, etc from overspray.  If you don't, you'll be polishing a much wider area.

Next, I used a spray can of the factory color purchased from the dealer.  ($15) Using quick, even, and steady strokes, I laid down a few passes.  The proper method is to hold the can about 8 inches from the surface, start more than a foot from the spray area.  Move the can into the area at a good speed and as you approach within 6" depress the button.  Keep the angle of the nozzle fixed, and the speed constant, and release the button 6" past the blemish.  Keep the can moving at the same speed.  Stop when you are 12" or more beyond.

By keeping a steady speed, you ensure an even coat.  By moving rapidly, you apply very light coats.  The thinner the coat the better, but don't move the can super fast.  Practice on a sheet of newsprint.  If you can lay down a coat that is fairly smooth, but you can still read the print, you are about as thin as you want.  After three or so very light coats, allow the surface to dry a little.  About 10-20 minutes.  Repeat adding strokes until the color density over the primer is the same as the rest of the paint.

Let stand several hours and then remove the mask.

Later that day, or the next day (the longer the better to allow the paint to fully dry.  In humid weather, this can be several days) you want to lightly wet sand the area smooth.  I use 3 grits for my touch-up.  I started with a 400 grit to blend the new to the old and to get rid of the rough texture.  Clean the sandpaper often by rewetting.  Then I moved to a 1000 grit to smooth the scratches and finally a 2000 grit to eliminate all the sanding marks.  Only sand enough to smooth, don't over do it.

Next comes the magic.  Go to you local auto paint supplier (just ask the local body shop where it is) and buy a bottle of each of the 3M micro-polishing compound.  This stuff is fantastic.  Start with the heavier grit and rub it across the painted surface.  Follow up with the fine compound.  When you are done, if you prepped right, there should be no visible proof that the scratch was ever there.

My tailgate came out perfect.  Only with the light just right and knowing where to look could you see faint lines in the paint where the new and the old met.  The rocker panel came out great too, but because the metal had been damaged, you could still see some marks, but at least the paint was uniform and there were no scratches.

One thing I've been very happy with is the quality of the Mopar spray paint.  It matches the factory paint perfectly.  For primer, I used Rustoleum auto primer.  For small areas like scratches and minor damage, the spray cans are very good at applying an even coat.  Heck, when I painted my Jeep, I did all the primer with rattle cans.  It came out great and saved a lot of money.

Christopher Siano
 

Subject:      Re: [RAM] Fixing that "First Blemish"
From:         "Douglas Stuetzle" <douglas@metricom.com>

   Guys,

Let me add 2 items to the primer (intentional pun) on touch-up paint.

Before you do any wet sanding, go over the entire area with a wax & grease remover.  If you don't, the sanding may not remove all traces of wax and whatever other oil (fingerprints) are on the finish. Sometimes sanding just grinds this residue into the paint.  If this happens, you can get fisheyes in the primer & paint.  If you've ever done a quick & dirty spray can job on your barbeque, etc, you've probably seen spots where the paint literally leaves a hole; this is a fisheye.  It's not a bad idea to use the remover at each step of the painting, like when the primer is dry & ready for paint.  It'll take off any stray fingerprints you may have left there.

Also, consider using a tack rag before priming and then again before painting.  this is a super-sticky cheesecloth that picks up any/all specks of dust & dirt just before you spray the paint.

Hope these tips help.  I managed, with no previous experience, to paint my car in a garage with pretty decent results.  I used a basecoat/clearcoat system which allows you to fix a lot of dumbo mistakes with wet sanding & buffing, so I learned the hard way.

Doug


 
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