Quoted from xTheBlackKnightx:Different process.
Clear coating a car bumper and pinball playfield are not same thing.
If you take a playfield to a car restoration shop, they are many times clueless, and do not know what to do.
Those that do, reject the situation due to potentials like wood warping and moisture.
If anything I am learning a lot from this read. I was hoping to find a place I could get a clear coat done for me if I needed it. I took a picture of a playfield to an auto shop where I had had some car work done. I think they are pretty good based on the high end hardware I see in there (Porsche Mercedes BMW even Lambo). He took one look at it and immediately started shaking his head, and said no way. At the time I wondered why it was such a big deal, after all wouldn't it be simple compared to producing beautiful paint jobs on those expensive cars? But now I see why. Your explanation makes it clear. With a piece of sheet metal on a car, they have a single smooth surface of painted metal that they can control very tightly. This piece of wood with random paint on it, all sorts of holes, and plastic pieces shoved in it is something else entirely.
After I talked to him a bit and said I would take it as is and he wouldn't be responsible for any imperfections or whatever, he finally said he would do it. $150 a shot though.