In this case, I got the bumper and it was already black and the clear was in good shape, so I decided it didnt need primer,If it was any color other than black/grey/white I woulda primed it, so I sanded the clear with 220, then 400 wet and 800 wet, then I cleaned the bumper of all sanding residue, sprayed some 3 coats adhesion promoter on the cleaned bumper.
then I began shaking the can of color on while the last coat dries, make sure you shake it for atleast 1 minute...and if you can get the can kinda warm it helps...if its cold i've found that warming up some water in a tuppaware and letting the can sit for a few minutes helps it flow out better. I did 3 coats of color, lightly but you wanna make sure you get everything covered evenly. With the color coat your not aiming for shine at all, just even color..so take your time, more light coats is better.
After the paint has dried for 30-45 minutes.....you have the option of spraying another coat of adhesion promoter for the clear...I didnt. On to the clear, first two coats should be verrrry light..coats 3-4 should gradually become "Wet" coats, which is when you lay it on heavy so that it flowsss out nice....but thats really the hard part if you dont know how to handle spray paint very well..Basically what your gonna want to do is, instead of being 8-10 inches away, you might wanna bring it in to 4-6 inches, and move fast, but do long strokes...almost like painting with a real gun, but you have to be really careful for runs. I've gotten to the point where I dont even take my finger off the button while doing a section unless i need to shake the can.. it really just helps it be a uniform coat of clear..
After you've got your 3-5 coats of clear on....leave it alone to dry over night..Its gonne be kinda shiny, but have a texture most likely. Wait atleast 24 hours. I waited 2 days before wetsanding it... when you wetsand make sure you keep the section you're working on WET, just like sex, the wetter the better. Depending on how much clear you got on there, if you did a lil extra, you might want to start with 1000 grit. then 1500, then 2000 or 2500, i've even gone to 3000 before, but you have to make sure you have enough clear for all that sanding. Do each step of wetsanding throughly and completely before moving on to the next. Then after that, polish it... if you have a porter cable or something, I just used m205 at speed 5.... take your time, and watch out for the damn edges... do the crevices by hand. thats pretty much it.
If you sanded and polished real good, People will have a hard time figuring out that its not painted with a gun.
Its not impossible to do a good job with spray cans, just a lil more difficult and a lot more sanding in the end processes to get it to look right, but you save money and your doing it yourself....I dont condone doing your whole car this way unless you really want to.. In that case I would reccomend a urethane clear with the catalyst in it....those cans are expensive though...bout $27 a pop.
