Recently I acquired a near mint condition Centigrade 37. The machine is freaking awesome: a real beauty and very *very* low use. There were only a couple issues with the playfield that I wanted to address:
1) Fairly deep scratches in the paint in four areas
2) Bare wood shooter lane
3) The beginnings of paint loss around the upper-right and bottom (1000 point) pop bumper

I decided on doing the scratch repairs using hand applied epoxy to re-level the scratches, followed by carefully sanding the repairs flush. The scratched areas would then be touched up with acrylic Createx paint mixed to match the surrounding color (blue and orange). Final step would be to brush apply fresh lacquer over the repainted areas so as to replicate the "grain" in the original lacquer coat.

Here's the original playfield appearence, with the left inlane area needing repair:

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Look closely here and you will see the heavy scratch (gouge) in the orange inlane. The lane divider was deformed due to somebody attempting to put the wrong kind of rubber around those posts (I removed it already) - and I think they used a screw driver which at some point slipped and did the damage. Anyway, I mixed up some West System slow-cure epoxy, and carefully applied it into the gouged area so as to be very slightly above the playfield surface. This then would be sanded down with 400 / 600 grade paper to be flush with the surface.

Also in this area, the blue surrounding the GE44 light bulb was significantly discolored, so I mixed up some blue then very carefully darkened it with black to blend in a little better. The blue area was then masked off and a very light coat of the new blue was airbrushed in. (I'm just using standard Scotch tape as the mask line here so you can't see it in the pic)

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And here's the blue area done, with the orange area yet to be fixed:
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The black key lines were re-done using Molotow black acrylic and a very fine brush, painted by hand. The final step would be to re-lacquer over the repaired area with brush applied lacquer. I wanted to replicate the "grain" in the original playfield surface so when re-brushing the lacquer, I was careful to stroke in the correct direction, and just as the lacquer began to tighten up I was able to get the grain effect so blend in with the surrounding area:

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The same technique was used to repair the blue areas just ahead of the apron, where it looked like somebody hastily removed and replaced the apron metal, causing gouges in the paint. Here you can see where I've already leveled and airbrushed the new blue layer on. Note the epoxy fill isn't perfect, and you can see hard paint lines where I'd masked off for the airbrush work. The un-level fill work was further fixed with additional brush applied paint and more sanding, and the hard tape lines were blurred out by very carefully hand sanding them with 600 to blend in with their surroundings:

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And again, these areas were re-lacquered using brush applied Behlen "stringed instrument" lacquer, un-cut and done with a very very fine hair brush. The final layers were applied and carefully brushed in to replicate the "grain" in the original lacquer coat. Final results:

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Pop bumper surrounds were also in need of touch up. They did have the original factory free-floating mylar platters installed, but the paint underneath was beginning to get beat up and sort of "thin" in areas. I fully repainted the right-upper orange pop surround and did a very careful airbrush touchup of the center "1000" bumper surround in blue. These areas required a slight adjustment of the original paint colors I'd mixed for the lower playfield.

Again, after the Createx was ready enough for sanding I lightly wore it down with 600 to give it just a slight "worn" look before clear coat. The bumper skirt surrounds were then re-lacquered with Behlen lacquer using an Ox hair brush (fine bristles). I didn't use any thinner or slowing agent, although the slowing agent in this case might have been handy to have. The final layer was a heavy one; feathered out toward the edges for blending. I didn't really try to blend in the "grain" of the original lacquer here because I was going to apply adhesive mylar platters around the bumpers anyway.

Here's a couple pics, before and after:

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The shooter lane also needed work. It was a factory bare wood trough, which I don't like - so I lightly sanded off the ball skid areas, and re-lacquered the shooter trough with about 10 coats, 600 sanded every other layer or so:

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Last thing I did was re-work most of the circular key lines around the inserts. All of them had slight wear, but I also really didn't want them to look 100% brand new after re-work. Using Molotow black ink and a very fine high quality artists brush, I touched up the key lines all over the playfield by hand. Those repairs were then re-lacquered as well for gloss level and protection. Here's how the "When Lit" came out:

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And here she is all ready for top side mechanicals to be reinstalled:

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Looking good. Going back together:

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This C37 is now fully reassembled and looking absolutely flawless. I'll post the story behind this amazing find next, along with more pics of it set up in position and playing. Shes a beautiful example of some of Gottlieb's finest work!

DropTarget:

I don't think it would be possible to "hand sand" something as small as a scratch repair so I had to improvise a small sanding tool to do the job. To do this, I glue-sticked the sand paper to a very small sculpting spatula about 1/4" wide and having a slightly curved surface (google "sculpting spatula" to see what I mean) so I could keep a portion of the tool flat with the surface while working with it. This type of tool makes it possible to do very precise work to a small area without affecting surrounding surfaces.

Intially using 400 grit open coat paper, I prepared pieces of the paper to closely fit the spatula shape. The sand paper was glued to the tool face and sanding was done dry, using small circular strokes with light pressure. I changed the paper alot to keep it cutting smoothly and accurately.

Lighting for this kind of work is extremely important. So a portable LED worklight (see #2 pic in first post) was set up and adjusted to reflect off the working surface so I could see how the sanding was progressing with good detail. Every so often, I'd use a light naptha wipe to better see how the sanded epoxy repair was blending. I also used some magnifying eye wear (Donegan OptiVisor) for very close-up acuity.

Once I had the repair areas sanded flat, I very lightly finished them with 600 open coat - sanding in the "grain" direction so the airbrushed Createx wouldn't telegraph through the sanding marks. In retrospect, this probably wasn't necessary as the "grain" was later found to be needed in the final lacquer clear coat for 100% conformity with the surrounding surface.

The sanding was then followed with the airbrushed Createx - more sanding - and then final lacquer coats. The repairs are basically impossible to detect even with bright light and magnification so I'm pleased with the outcome.

The "next level" - meaning getting results that are so good that its virtually impossible to tell anything was done I assume. For that you will need some decent equipment - I have 3 airbrushes and love the Iwata NEO TRN-1 for spraying Createx. Even using the NEO, which is designed to spray acrylic, I thin it down about 10% for really smooth results. No need to try and cover in a single coat.

The color match you do is critically important. For the work you see here, my wife and I worked together for a couple hours getting the orange and blue just perfect. The ONLY way you'll know if its spot-on perfect is to actually apply a little of your test color with a small brush (1/8" wide) and dry it in place with a hair dryer on low heat. You will have to paint the sample directly on the playfield surface - dry it - look with very good natural light. Only in this way can you see the test color laid right over top of the color its supposed to match. After the test, just wipe it off using a piece of paper towel wetted with acrylic paint thinner. It won't hurt the lacquer finish underneath, and you can do this as many times as needed to get the color JUST RIGHT. I sampled my color many many times this way before committing to it. If you're not sure how to mix custom colors, get a color wheel and see how it works. (google "color wheel")

Spraying acrylic is pretty easy, but getting an absolutely perfect surface finish does require some attention to detail. I use magnifying cheaters eye glasses (Walgreens +1.5) to see high detail in the paint finish coming off the gun. Light has to be directed so you can see fine detail in the reflection. You want the paint to go on like glass - not lumpy or dull looking. It will dull out as it dries, but it should look wet and smooth when it goes on. That's why I thin the Createx down just a little... so it has time to level and resists the tendency to go on too dry with a dull texture. I find it takes two very thin coats for good coverage like this.

The lacquer also has to be perfect. No good way to spray it I've found. So I brush it on with a VERY fine hair brush about 1/2 to 3/4" wide. Its just a small artists brush. I put the lacquer on full strength - not thinned at all. Brush it on one coat at a time and allow to dry between coats. Maybe an hour. Be sure to brush in the direction of the "grain" of the existing clear coat. Due to the rapid dry time, you'll have to clean the brush between coats. The lacquer will blend in easily with existing top coat. On the final last 2 coats or so you can drag the brush over just as the lacquer tightens up to create the "grain" effect in your repair. Use high quality lacquer. I use Behlen high gloss, which is supposed to be very very good. At least the price tag says so.

If the color is matched perfectly, and the lacquer repair area is blended in carefully, the repair will be pretty much invisible to the eye.

- Bill.

I haven't done anything to address the cupping. And as you correctly surmise, they're ALL cupped. It does affect play. Since this is a like new factory original playfield, I didn't want to 2PAC clear coat it, even though doing so would be relatively easy.

Thank you!