TJEvans said:
With the appliance paint....do you sand after waiting a week and before applying the successive coats?
In other words, is it sand, light coat, wait week, sand, light coat, wait week, sand, light coat...etc?
or just sand, light coat, wait week, light coat, wait week?
Just to clarify this a bit, I think that the best way to get good results from this epoxy paint is to spray a LIGHT coat over your part, then wait about five minutes for the aromatics in the paint to flash off a bit, then spray a SECOND light coat, and try to cover the areas you missed with the first light coat. Again, wait five minutes, then follow with a THIRD light coat, then wait five minutes, spray ANOTHER light coat, and so on...
Painting your components with that method allows you to gradually build up to full coverage in one day; each light coat you apply will help you to get full coverage. Professional autobody painters I've spoken to also refer to it as a "mist" coat, or a "fog" coat; regardless of the terminology used, the point is that you apply the paint in several stages within about thirty minute time frame, so that you've got complete coverage in those 30 minutes. After that amount of time has passed, you allow the paint to dry for a week (or longer), then add more light coats ONLY if you have any thin spots that still need to be covered.
NOTE: You will ONLY have to wet-sand the ORIGINAL paint with 400 grit paper to give the NEW epoxy paint a surface to stick to; AFTER you've let the NEW paint dry for a week, you wet-sand it again ONLY if you have any flaws that need to be removed, such as sags, drips, runs, dirt, or bugs in the paint, or whatever it might be that screwed up your results. You'll ALSO have to wet-sand it again if you need to apply MORE paint to cover any thin spots that were missed the first time, or to cover the areas where you've re-sanded to remove the flaws (sags, drips, runs, etc.)
Whenever I wet-sand a painted surface, I add a few drops of household dish soap to the water, which helps to keep the paint from loading up on the sandpaper. In fact, I usually put a few drops of the soap directly onto the sandpaper itself, especially whenever I feel the paper beginning to "load up" with paint; you'll feel the paper begin to drag slightly across the surface of the object you're sanding when the paint begins to build up on the sandpaper, which tells you that it's time to clean / rinse the paper again, and check it for paint buildup. If the buildup is minor, I just wipe the paint off with my finger, then resume sanding; if the paper is wearing out, I switch to a fresh sheet, put a few drops of dishsoap onto the paper, then continue sanding. I sand large / long parts in a (rubber / plastic) 55 gallon trash barrel that I bought at Lowe's specifically for sanding large parts; it is sturdy enough to hold a lot of water without buckling; I sand smaller parts in a (rubber / plastic) dishpan I got at the local supermarket. Obviously, those containers are ONLY used for wet-sanding; I don't put any oil / solvent into them, because I don't want residual chemicals to contaminate things I'm going to paint.
One good bit of advice I can give you is this: ALWAYS USE A SANDING BLOCK, without exception; if you sand without one, your fingers will put uneven pressure on the paper, and you'll actually be sanding grooves into the surface you're working on. I prefer to keep several sheets of sandpaper soaking in a container of clean water, so I can switch to a fresh sheet of sandpaper quickly. Be CAREFUL when you sand corners, curves, edges, or ANY area where the surface isn't perfectly flat. It's VERY easy to break through the surface paint in those areas, because the paint tends to be thinner there. Keep in mind that when you wet-sand, you only want to prepare the surface to accept new paint (or primer) on top of it; you're ONLY giving the surface "tooth", which helps the new paint or primer to adhere better. You're NOT trying to REMOVE the original coating completely; you're just making it easier for the new paint to stick to the old coating.
OK, I've probably beaten this horse to death by now, but I only want to make sure that you understand how to get good results when you use spraybombs. I ONLY use spray paint; I don't have a compressor, or a paint gun, I don't have access to a spray booth... hell, I don't even have a damn GARAGE to work in, just a crappy carport, so I've had to learn how to get good results with spray cans under less than optimal conditions... so I'm hoping that this helps you to get the results YOU want, without a lot of headaches in the process... if you keep these points in mind as you work, maybe you'll be able to avoid some of the problems I've encountered over the years...
Of course, I'm hoping that JRK / Joe will correct me if I have any of this wrong; I've done a fair amount of spray-bombing over the last thirty years, so I have a good idea on how to accomplish this, but I'm NOT claiming to be an expert.
Good luck; if any of this isn't clear to you, ask any questions you might have, and we'll try to help you figure it out.