Apologies for the length of this post, but if I tell you what I know it may be easier for someone to tell me what I NEED to know. I painted a lot 30-35 years ago. State of the art then was acrylic lacquer primer. I used mostly DZ3 and DZ7 as a primer surfacer. Lay on a wet coat, block it, and repeat until it's straight. Top coat was acrylic lacquer with a clear coat, or a few years later later we used Centari or Delstar acrylic enamel topcoats. I have almost no experience with painting since those days, no experience with base/clear modern stuff or epoxy/urethane. The previous owner of my roadster roughed out the body and shot it with DP90 primer only. A few years in the sun has NOT been kind to the DP90. I like that look, so I've decided to dust off the old tools, finish block it, and shoot it with SEM hot rod black satin as a topcoat. I've got some bumps and waves and 36/40 sand scratches to deal with. I still have my old DeVilbiss JGA 502 suction type spray guns and hate to experiment with something new unless I have to. Now the questions. Assuming I can still buy DZ7 lacquer primer, will that be ok to use over the remnants of the DP90 to get it smoothed out and will it be ok under the topcoat? Or, Is there a better modern alternative? Something that dries fast, fills well, and sands easily. Once it's blocked and smooth, should I shoot something on to act as a sealer over the dissimilar undercoats before the topcoat? Recommendations? Ideally something I could sand the dust nibs out of before topcoating, as airborne floaters will likely be a problem in my garage. Or will the 2K topcoat be ok over the old DP90/DZ7 and whatever combination base without a sealer? Just give it a thin, uniform coat of primer before topcoat? Don't want anything to lift or curdle. Applying acrylic enamel topcoat back in the day seemed to work best with a light tack coat to make it sticky, a second wetter coat for color coverage, and a third wet coat for for gloss and flow to make it shine. Will applying the SEM urethane topcoat be similar, and if not, how should it be applied? Not going for a shine with the satin but I'd like for it to have little or no orange peel when it's done. Thanks for any advice you can give me. I'm sure I'll have more questions as I get into it.
Thoroughly block the DP. Prime again with DPLF (lead free) color of your choice. Apply 2 part urethane primer filler according to directions. Block/prime to your satisfaction and apply color of your choice. Use the JGA Yes lacquer product will work but you will be trapping old chemistry between superior products.
You got a epoxy primer on there. Don't go backwards putting lacquer on it. Block it, re prime, hit it with 400, top coat it
Try K36 to replace the Kondar; it will build nearly as fast, but will sand easy and not shrink ( if you allow it to full cure ). Follow the PPG data sheet.
Agree with most of the posts, stay away from the old stuff unless you are looking for period correct perfection. First thing I'd do is to take a big area down to bare. If the DP failed on top, it may have alllowed water to soak down to the bare metal. Epoxy is water resisitant, NOT watproof! I used to do lacquer back when, too. Today you take out all imperfections in the primer/surfacer stages, then just lay the paint on top of it. Most guys use an epoxy sealer or etch over bare steel, then go to a urethane surfacer primer to fill scrathes and minor lows. I prefer House of Kolor Epoxy all the way through, but that' just my predjudice. The new urethanes lay down like enamels, though the basecoats feel more like lacquer (though you cannot sand base and apply clear, you will see sand scratches, go directly from the last base coat to clear) Single stage urethane looks more like the old non-clearcoated paints, go on like Centari. Sanding and buffing is much more difficult that the old lacquers. You have to start with an 800 or 1000 grit wet, depending on how orange peel-y your final finish is. Then progress to 1500 and even 2000 or 3000 grit. Then microfine compound and polish. Good luck...any more questions just ask.
Very well put, Mark. The JGA will spray the urethane primer or color/topcoat and urethane clear OK. It may have a somewhat large tip size (.072-.074) for basecoat. I was at Harbor freight yesterday and you can get a nice little (gravity feed) gun with a 1.3 tip (.068) for under 25 bucks, which would work good for basecoat. They had a 2 gun gravity combo--touch up (.9-1.0mm) - and regular size (1.3-1.4mm) for under 50 bucks. At those prices you can throw them away after using (well, maybe). This Garage Paint 101 tech post I did may contain some useful info for your situation. http://www.jalopyjournal.com/forum/showthread.php?t=14597&showall=1 overspray
Huh? Do you gamble much? This primer sat out for years, and now you want to paint over it? Primer should be painted right away or it sucks up stuff that you'll recognize later. Strip it. It's a tiny (valuable) roadster! Strip that thing bare and KNOW what you've got.
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