Yeah, there were more than a few steps left out. Actually I was looking through our photos when I found that set so I tailored the narrative to the pictures I had. In fact I cheated just a little bit on that too, but it is what it is.
OK, the missed parts. In order to get to that smooth shiny paint job you have to do a bunch of other things first. The basic rule is that no coat of material will ever be any smoother than the coat under it, so you have to start with the finish you want to end up with. In other words, its all in the prep.
First all the parts have to be clean. I wash them and wash them and wash them, then I wipe them down with acetone, then I wash them a few more times (dawn dish washing soap), and finally I wipe them down with acetone again before I begin sanding or grinding them. I do this even if the parts will be taken down to bare metal. Keep this in mind, sanding does not remove wax, it just grinds it in. Well, its even worse these days with silicon in so many car-care products. You see guys complain about fish-eyes in their paint? Well, they didn't clean before sanding in many cases.
Anyway you clean it and then you sand it. If there are dents to take out or welding to do get it done. Have all of your metal straight and flat (or round) to within at least an eight of an inch. Anywhere there is bare metal hit it with the grinder (80 grit) and if more than half the part is going to be stripped go ahead and strip it all. Do not leave bare metal exposed, wipe it down with acetone and immediately shoot it with 2 coats of epoxy to seal it.
Now use your filler, and use it sparingly. When ever I need to use actual filler I use Rage Extreme, but mostly I just skim the parts with Iceing (a flowing polyester filler) and then go back and sand just about all of it back off. Also, I never sand anything without a block, right from the start. That is the key to a perfect finish in the end, that right from the beginning you block sand and nothing else. Because I only do motorcycles I have the luxury of not needing power (orbital) sanders; I sand everything by hand.
Here comes the monolog: Lots of guys have trouble cutting and buffing the final paint job because they sand through the clear coat into the base coat. Sometimes new painters try to compensate for this by shooting the paint heavier around the edges, leaving a rolled edge sometimes and more often runs. The thing is if the parts are sanded flat right from the beginning there is never a lip that needs to be sanded down. So I begin my block sanding right from the start and it makes it ever so easy as the job progresses.
Back to the job. So now the metal (which may also include sound original finish in some cases) has deep sanding scratches and its also got two coats of epoxy over it. The metal is reasonably flat and straight but not precisely so, so its time to work. I slather a very thin coat of Iceing over the part, let it set up (2 part catalyzed product) and then begin sanding, usually with 180p or 220p paper and my everpresent block. I will sand them parts flat at this time using the underlieing epoxy essentially as a reverse guide-coat. I'll sand down to it, and through it in many places, and any lows will have been filled by the Ice'. Then I'll shoot two more coats of epoxy over it and let that sit for about 2 hours. After that I will shoot three or four coats of 2K primer, giving each coat plenty of dry time inbetween coats. We aren't talking tack-test here, we're talking bone dry.
Oh, to answer your earlier question, yes - up to this point I often do the work outdoors. Its just primer and its all going to be sanded and I live way way out in the country where the fumes will never be smelled by anyone
Then I let is set at least over night before shooting on a guide coat, which is the stage you see it in in the pictures where the red primer is sort of splotched over the parts. For guys who have not used a guide coat consider what we have and where we are. There is the metal and then there is a nice sealer and filler layer which was sanded dead flat with progressively finer sand paper (moving from the 220 up to about 400) and is topped off by a nice sealer of epoxy. On top of that there are several costs of high build primer and on top of its bumpy surface there is this dirt cheap rattle can primer in a contrasting color (very important) that you stood back and dusted on for no other purpose than to go right back and sand every single bit of it off. And that's the trick. You got gray primer, then use some red rattle can cheap primer - the cheapest stuff you can find. Also, if you are a painter you can just use anything you've got left over, just over reduce it and add a little black or white as required.
This is the most important step in the paint job. By this point in the game you have progressed up to about 400p~600pgrit paper and its on your block. All you want to do is sand the dusted coat of paint off of your high build primer. Once its gone quit sanding in that spot and move to a spot where its not gone. The very moment its all gone you have a dead flat dead smooth piece in front of you. There is only one step left. Now we move indoors. I give the parts a wipe-down with a degreaser (PPGG Omni product), wipe it with a tack rag Mix up another batch of epoxy, wait out the incubation period, and shoot two coats on as a final sealer. I reduce mine 10% with acetone. And now I'm on the clock. With the epoxy I use I've got 48 hours to get it painted from the time I shoot that sealer.
Keep in mind that by the time you shoot that last sealer coat that all the surfaces are as flat and straight as they will be in the final job, the only difference really is that the surface hasn't been polished yet.
OK, then you do stuff and we can go into products and effects and how-to articles and all sorts of recommendations for equipment (I'm an Iwata man to the end) , but we'll save that for later.
And finally its sitting there and the basecoat is dry, and you've removed any nibs of dust and got it tacked and its time to clear it. So you chose a good clear (I generally use House of Kolor UC-35), mix it up, shoot it on and then wait a day or two and now its time to cut and buff it.
At this point in the game the suface may have dust in it, a bug may have taken a hike through it, it may be a bit bumpy, it may have runs in it, it may have a sag or two. Who knows? So you begin by sanding that clear coat. This is the cutting part of cutting and buffing.
I like to start my cut with 800 grit paper and using the clear coat as if it were a guide coat I'll - with my block, always with my block - sand off about 80% of the gloss of the paint job with the 800p. Then I'll move up to 1000p and sand off about 10% more of the gloss. Then I'll move up to 1500p to finish taking all of the gloss off the clear coat. Anywhere there is a speck of dust it will look like a little pimple. I give each and every one of them personal attention and I sand them off at the 1500p stage, one swipe at a time. I sand with continuous water to rinse with and a bucket of soap/water (Dawn dish soap once again, just a few drops in a 5 gallon bucket). Then I give all the parts a final light sanding with 2000 grit.
Next its time to buff. There is nothing special about my technique. I use a Makita buffer and I have several backing plates and pads, my current set comes from TCP-Global, its by "Custom Shop" but that's just because my local paint supplier, who sold 3M stuff, closed up shop and now I get most of my supplies via the brown truck.
I use 3M Perfect-It II, first with a wool pad just to knock the haze off. Then I move to a yellow pad and the Perfect it II. Then I go to a black pad, once again with Perfect-It II, and then I finish up with a separate black pad and McQuires (sp?) Swirl Remover. I am not a bit ashamed to say this, I am really good at cutting and buffing
At any rate a big part of my point is that if you start off doing all of the sanding with a block, and you sand all of the parts several times over the course of doing the job, and you are always using the same blocks (I have many) with ever and ever finer paper the chance of you sanding through anything just keeps on decreasing and of course with every sanding it all gets flatter and straighter.
And that's all there is to it.
