Apologies in advance for the long post.
Background: I've clearcoated three playfields in my garage using Omni 161, but I've never been entirely happy with the results, due to the limitations of my equipment and environment. Plus, even though I take lots of precautions, I get nervous about having aggressive carcinogens leaking into my house from the garage and decided it's not worth the risk to my health. Plus, the one supplier in town who will sell me Omni 161 is a pain to work with and I don't want to deal with them.
About a year ago I bought a 1966 Williams Hot Line in decent shape, but with a little paint flaking on the playfield and now I think I want to touch it up and lock it down with a clearcoat, so I've been going to auto body shops in the area to see if they'll spray it for me. The first nine I visited refused to even entertain the idea of spraying something other than a car, but my local Maaco shop said "no problem." We talked a bit about it and there are a few questions and concerns:
1. They use Sherwin-Williams products rather than PPG, so is there a S/W analog to Omni 161 with the same properties that you'd recommend?
2. To prepare a car, they usually give the surface some tooth by sanding with a low-grit sandpaper and asked about doing that to the playfield. Is that necessary? Would a Magic Eraser scuff it up enough to let the clear stick without damaging the art?
3. Before clearcoating, they pre-treat cars with a cleaner that contains a bit of thinner. They're afraid it might thin and smear the artwork. Is that a danger for the original Williams printing or the Createx airbrush paints? What about waterslide decals? Would it be better to bring a can of naphtha and ask them to use that?