more about the paint
had some questions via PM so I'll answer here for the group as best I can..
one of the good (and bad) things about working at the auto craft shop on post was that I had a full time tech there to answer questions and help out when it got technical.. good dude, and he did all the mixing and was there to look over my shoulder when it was time for teh fun stuff (didn't hang out much for the sanding part!)
I only have experience within the limits of what he taught me.
I used a 2-stage paint, urethane, from a brand called Lesonal, which I think is sort of a mid-grade brand.
By 2 stages that means color in one and clear in another... really you might think of it as 3 stage because priming isn't figured in those 2 stages.
The HVLP gun I used belonged to the facility, I didn't buy it.. so don't know what brand it was.. probably (again) a mid grade model as it's purchased for MWR (morale, welfare, and recreation) reasons.. the booth was a pro type, with an evac/recirc system, floor drains, compressed air, and heat.
Some consdierations for the facility you paint in.. you obviously want it clean, as any minute pieces of lint/dust or whatever is more than likely to get kicked up and the spraying activity functionally acts like a static creator.. as material gets in the air, it will be drawn to your paint, thus the booth is intended to have a flow (air moves from one end to the other). Upon advice from the tech, I wet down the booth floor with water before each stage.
Also, pay alot of attention to organization in the booth.. when you've got open paint with a hardener applied to it, you don't want to be screwing around moving stuff in the booth, as it continues to set up over time, even in the gun, and can clog your spray. I actually rented two booths at once, one to do the tub/chassis, and one with all the doors, hood, and hinges on sawhorses or table tops.
My windshield frame was knew (from 4wd hardware or q-tec, don't remember, had bought it several years before).. and painting it took some special angles as the INTERIOR of the frame was also raw primer from the factory, and I didn't want it rusting out from the inside, so I tried to do my best go get a bunch in any hole that was open.
SUPPLIES: bought all mine from the shop but I got a oversuit at Napa (20$) and a mask at Lowes (make sure you get the filters that work for isocyanates, the filters are different.) Get the good automotive masking tape (alot of it) and get it in different widths..
BIG ROOKIE LESSON: you wan't to paint a "wet edge".. as you paint across the sheet metal you want to see a wet-ish surface from your fresh paint, which means you have to go slowly enough that you're actually building a wet surface.. I was so concerned on the Probe about getting a run that I went too fast, and when I did that, I got sort of a "dusty" paint texture first, which doesn't give you the smooth and thick surface you're going to lay the (thinner) color on.. and it made wet sanding that much harder as the texture was that much rougher..
PRIMER COAT AS A REHEARSAL: for the CJ I think I did 3 coats of primer... don't remember if it's because I needed it, or if I just had enough paint mixed to do it. Either way, when you paint primer don't worry about runs or drips too much.. you'll wet sand out imperfections anyway. It's a good time to practice yorur stroke/technique, and I'd recommend using it as a "rehearsal" for your color coats.. you'll start finding out that there are angles or corners that you'll need to narrow the spray fan on, you'll figure out how easy/hard it is to move around the vehicle (sounds simple but when you've got a can of really expensive paint in a blow gun attached to a heavy air hose and you're walking around in a jump suit and mask/filter, you tend to stress a bit about things)
PRIMER AS FILLER: depending on the surface flaws, you can identify certain areas of the vehicle that you want some extra heavy primer on.. on my tub, for example, I did extra coats of primer above the rear wheel wells, where the factory spot welds are that you normally seem some dimples/vairations as you look down a jeep lengthwise.. if it's a relatively small or thin flaw, your primer might acutally work like a body filler.. so, mentally retain or have a system to remind yourself where you want some extra thick layers on..
DEGREASE AND TACK CLOTH: you'll want to do a good quality degreaser (all strokes in one direction, doesn't matter what quality paper towel you use as you'll tack cloth it anway).. they sell this at paint supply stores and your local one can explain it to you.. tack cloth is like a sticky cheese cloth that picks up any lint or residue, which you do just before painting.. it's all part of the very anal and detailed prep..
PAINTING: with metallics you want pretty good pressure on the gun and a pretty wide fan, that way the colors/metallics get spread more evenly, and you overlap your spray with each stroke to blend it.. otherwise you'll get 'tiger stripe' or streaky color.. did two coats the normal way, and then one "proof coat", which was holding the gun higher/further away from the paint and painting at 45 degree angles.. this futher eliminates chances of streaky colors..
TIME BETWEEN COATS: each manufacture has a tech data sheet that tells you how long between coats and what the "flash off" time (time it tacks for those hardeners and chemicals to chemically react on the surface and start to bond/dry) requirements are.. depending on what brand/system you use, I'm sure they vary.. read the Tech data sheets. Since I was using two booths at once, generally speaking, from the time I moved from one booth to the other, painted what was in the second booth, and got back to booth 1, the stuff in booth 1 was ready for another coat... I'd figure it was 15-30 minutes minimum for flash off..
TIMING: every step of this process too me longer than expected, and one thing Steve (the tech) did a good job of coaching me on what NOT rushing to get something done that day.. if you put yourself in a bind where you're trying to rush to get it done, highly likely you'll ruin all the work you've done... I delayed my actual paint by one overnight to get a full day to set up the booth, mask, and degrease.. then I came back a second day and degreased again, tacked and then sprayed.. then the truck and parts sat in teh booth all day baking (I'd guess about 115 degrees or so).
MASKING: a learning experience.. it takes forever and you have to sort of "be the paint" and imagine where you'd go..
MASKING II: use fresh masking tape/paper every time.. old stuff is dirty (bad) and with all the wet sandng you do, it will hold moisture.. on my probe I forgot to replace the masking paper on the windshield washer nozzles.. those nozzels (dead center of the top of the hood) went into the booth damp.. I sprayed the color and clear, and then when we put the heat to it, it forces the water down and out of the tape, and made a loooooong sidewinding impression in my clear as the water ran for the front bumper.. fixed with a buff/polish but very annoying detail that nearly ruined the single largest flat surface of paint..
