I have gotten several PM's about painting and finally decided to do a little guide to help out.
Basically there are 2 things you need to remember:
1. Cleanliness is next to godliness
2. Take your time
With this being said, make sure when getting your paint and sandpaper to pick up cleaning materials such as:
- Lint free cloths/towels
- Latex gloves (not necessary, but some like it)
- Resporator or breathing mask
- Wax and grease remover (not laquer thinner or acetone)
- Tack cloth (not compleatly necessary for most applications)
- Good car wash soap
First start the project by cleaning the parts or surface to be painted with hot soapy water then rinse.
Use your Wax and grease remover. Put it on a clean rag and apply wet (not soaking wet, but you know) then dry with another cloth. Do small area's at a time. You need to make sure to whipe clean because some residue can be left behind causing problems later on.
Now its time to prep your panel. Depending what you need to do your next steps can vary. If your doing rust removal, ding/dent removal, or just painting.
I'm going to just stick with painting on this one.
Assuming your panel is in good shape prior to paint you have 2 options you can do:
1. Wet sand with 400 grit
2. Dry scuff with scuff pad
I prefer the wetsanding because it leaves your area dust free.
Some tips in either case, since your trying to get to the same place with both methods:
- Even pressure
- Long strokes
- Don't focus on hard edges (with less surface area, it is much easier to sand too much)
You may need to put masking tape on spots you do not want to sand if say your doing a hood and don't want to sand the fenders. Put a couple strips on the fenders to protect them.
Sand or scuff untill you get a uniform dullness over the entire panel. Assuming you have clearcoat this is much easier. Keep your wetsand paper wet and rinse the area often to get rid of excess crap.
If you run into chips in the paint, feather the edges by lightly sanding in a small area directly over the chip. Make sure to watch what the paint is doing. You don't want a low spot in the middle because this will stick out badly when your finished painting.
After you get to the uniform dullness, wash the panel again with hot soapy water and again, use your wax and grease remover to get rid of any traces. (Some companies have a "final step" product before paint that is simular to W&G remover, but this works fine.)
After your panel is dry, mask off anything that isn't going to be painted and its time to spray. If your new to painting or just want to check yourself, use a junk piece of cardboard or whatever to get your speed and distance down. Try to keep anywhere from 6-10" away from your panel depending on wind conditions and flow patterns. Also, make sure to overlap your strokes half way to get a nice even coating. Think of it like this:
Your spray pattern is say 4". Then every time you make 1 pass, go up 2".
If using a spray gun, a 1.5mm tip would work well for doing color and clear. If rattle canning something, just read the instructions on the back of the can. 6-10" away with a nice even coating. You will want to put at least 2 coats of paint on in either case waiting the recommended time between coats (generally 10-15min)
If you have any sags, runs, dust, or other debris, use some 600grit sandpaper and lightly sand. If you go through your color you will have to re-shoot the panel. If not, your good to go to the next step.
Then if your going to clear coat, do the same as above. The biggest problem with clear coat is that its clear (dur) and makes it hard to see if your putting to much or too little on the panel. As a guideline for me, its better to be wet than dry. Meaning, if you shoot your clear coat too dry, you will have severe orangpeeling or worse, just look like overspray. This is a big waste of product because you will have to wetsand with 600 grit and reshoot the panel. If you do have runs, its not the end of the world. These can be worked with 1000 grit sandpaper and eventually polished out later.
After you get your 2 coats of clear on its time to let it sit. Without a drying booth, this is generally 3 days till cured enough to wetsand and polish.
Grab some 1500 or 2000 grit sandpaper (depending on how much orangpeel is present) and go over the whole car. Again, keeping away from the hard edges and using even pressure with long strokes. Again, keep the area wet and rinse often. Also useing a body squeege works nice to clear the water and see where you are at. Check often so you don't go though your clearcoat and have to reshoot.
Once done with this step the car should look dull again. Get some swirl remover (professional grade), shake well and often, and start polishing doing small areas at a time. Once your satisfied get a fine cut polish and do it all over again with a different rag or buffer head since the one used with swirl remover is contaminated with the other product.
Once finished with that, you should be good to go. Remember: Do NOT wax your fresh clearcoat for at least 3 months. Even though you can touch it, the clearcoat is still curing. Wax closes the tiny pores in which the chemicals release. If these are closed, the clear coat will bubble up making you redo this all over again.
Hope this helps.
Here are pics from my little crap today.
Keep in mind that today was a horrible day to paint. It was windy, cold and raining... but for me, the show must go on.

Clear coat was comming off the hood.

Here is an example of feathering. Trying to blend the high parts (clear coat) with the low parts (paint color). Even though your talking about very tiny thicknesses, these will show up on your final product.

Here is a comparison of wetsanding vs not

Again

Panel ready

Sprayed with 1 coat of flat black shaker can

There you can see tiger striping which is caused when spray patterns are not overlapping. This was cause by not having enough light in the area to see the problem. Also, a second or third coat of paint would help this.
Again

Examples of proper technique


Overall job
4 out of 10

Color is not the same. Bad tiger striping. Few sags.
These things do not concern me because its the battle hatch... that and I ran out of paint

. This took me 4 10oz. cans of flat black to do 1 thick coat on the hood, bumper, headlight covers, and fenders. If doing to do the same, I would suggest 10 cans of 10oz paint or more depending on the color. Lighter colors covering dark colors will require more paint or a primer coat of a light grey.
Good luck and if you have any questions or comments, post them here.
_________________
I have no idea what I'm talking about. I'm only here for suggestion.