Those, just for reference, are 'inserts.' One thing you can do it to crank up the back feet; makes for a funner fast-moving game. And yes, funner is a word.

Clear Mylar circles can be stuck to the cupped insert. Building up the cupping to a better surface. This is a reversible fix.

Where do you get "clear mylar circles"? I have the same problem on a machine or two of mine. By they way, I've got the rear legs up about as high as they can go and I still get balls stuck on these lighted inserts. Thanks.

I like to clean the area to degrease it, level the playfield up and mix a little 2 pack lacquer up in say, the cap off an aerosol can and apply a few drops onto to recessed insert. It levels itself out, seals the insert against future sinkage and stops the woodwork from getting any further damage.

solarez gloss uv cured resin - https://www.amazon.com/gp/product/B00MGSB6MK - works pretty well and process is similar to the lacquer:

- level playfield
- drop in enough solarez to fill insert
- put a clear plastic cover over area to flatten the doming from surface tension - I used a piece of a thick paper sheet protector
- shine black light on it to cure the resin
- peel off the plastic and done. No waiting or shrinkage like solvent-based solutions.

Ok, some great information. I have a couple of clarifying questions. First, when you say "level the playfield", you mean that it needs to be adjusted so that it is level in ALL directions, not just left to right, correct? Left to right AND front to back? Also, can you clarify what you mean by "paper sheet protector"? Is that the clear plastic that we used to use on a 81/2 X 11" sheet of paper, like for protecting a report of some kind while still allowing a person to see the text through the protector sheet? I assume you cut the plastic protector sheet to the size that you need, apply the resin to the playfield insert, put the plastic protector on top of the insert, then use the blue light to cure the resin, correct? If so, what stops the plastic protector piece from getting stuck to the cured resin? If it sticks to the plastic insert, why won't it stick to the protector sheet? Sorry for all of the questions, I'm thinking about doing this and I don't want to screw it up. Thanks.

In my post, I meant that the playfield itself needs to be perfectly level only as the lacquer, being liquid, will find the lowest point unless its base is level. Basically, you'll get runs of the stuff where you dont want it
I have never tried the other approach so cannot comment.

OK, "Classicp....", I get what you mean about leveling the field. We are saying the same thing. What is "2 pack lacquer"? I'm familiar with 2 part epoxy, but not 2 pack lacquer. Can you give me more info on that? Sounds like the simplest way to go. Thanks.

It's the same top coat lacquer as used on a car with metallic/mica paintwork.
I mix mine up from a 1ltr can (about a 10th of US gallon I guess) by filling an egg cup full, putting that into an old, clean cup, and half an egg cup of the hardener ( 2 to 1 mix ratio) and that too goes into the cup. Then mix it up with a small brush, and apply. It will cure rock hard in about 20 minutes @20 degrees F.
Important: Do bear in mind the safety aspects when using this as it is toxic so take sensible precautions in handling, mixing and use in a very well ventilated area. Like anything, safe enough if used correctly.
Edit: 2 part - 2 pack, same thing US/UK terminology

Ok, I think I got it. That was helpful. Thanks!

Bought these on Amazon and they seem to be doing the job. Some inserts worked fine after only one, some others took a few.
84A122FD-8865-4168-B7F5-3393406BD918 (resized).jpeg

Bought these on Amazon and they seem to be doing the job. Some inserts worked fine after only one, some others took a few.

99215238-9F56-4696-BC83-E9E31FECF8C0 (resized).jpeg

Simple way to fix cupping on inserts. Super easy and they do their job.

TheEMScoreKeeper.com $5 for a full set of Invisible Mylar Insert Stickers. Multiple different sizes. Free shipping.

Thanks for posting this. I use Solarez for tying fishing flies, I never thought of using it to level inserts, this is brilliant.

Thanks

Alberto

Were you up drinking and spamming threads all night?

oops ... didn't see this.

roughly level in all directions is good enough. The solarez is thicker and doesn't run as easily, so it just needs to be approximate. I use a bubble level similar to this:
https://www.amazon.com/Circular-Measuring-Motorhome-Turntable-Phonograph/dp/B09KBMPL3Y

the cheapest bubble level you can find is fine, and often resting the front of the playfield on the rail is good enough for level

the sheet protector material is just mylar, tho I switched to something like these as they are thicker:
https://www.amazon.com/gp/product/B07WMS6F4P

the cured solarez doesn't stick to mylar.

to cure the solarez, I use this:

https://www.amazon.com/gp/product/B07G31SQZ7

the advantage of filling the insert with a liquid is you get a flat surface. Sticking self-adhesive mylar discs on is a lot easier but if you have a deeply cupped insert you may want to use a small one(s) in the middle and a larger one on top to try and fill the hole.

filling the insert with a liquid takes a little more care to fill the right amount ... tho it kinda depends on how perfect you want it to be.

if you overfill, when you put the mylar on top and possibly shift the mylar around a little to distribute everything, you can smear the excess onto the playfield surface. I usually hit the insert with 99 seconds of light, repeat if the mylar doesn't want to peel off easily, then remove the mylar and peel off any of the smear - if it's thin it'll break off the thicker stuff filling the insert, then UV light it again.

if you screw up, the solarez will peel out. The less fully cured, the easier it comes off. It sticks ok to plastic, but it's not a chemical bond. If you left some wax on the playfield next to the insert, it won't stick to playfield ink either.

If you have inserts with artwork screened on or weak playfield ink, ymmv.

keep in mind I'm doing this stuff for pacific pinball museum machines that are played daily. They are generally not beauty queens. Playability and the immediate cure time is the most important thing. Cupped inserts affecting slow rolling ball travel is so common that a perfectly flat playfield on an old EM seems odd I only solarez if the insert can't be removed and reglued level with the hole edges or the cupping is deep enough for a ball to hang up.

if you just have a minor ball hangup issue and don't want the insert very flat, I'd just use the self-adhesive mylar ... tho if the insert isn't something you have a precut shape for, then the liquid is probably easier and if you err on the underfill side, you're not likely to have to peel it out and try again. You can layer the solarez if you need to.

I appreciate the info and the links. Will have to give this one a shot and see how it goes.

The note about the solarez not wanting to stick to paint or wax is nice to know.

it may stick to paint. I've always had enough wax still on the playfield it's never lifted any ink if I peel it up.

I guess the ppm has lots of scrap playfields, so in a few days I can try getting down to the ink and seeing what happens if I cure some solarez onto it. I'll see if I can find a playfield with screened artwork on an insert and try peeling cured resin off that also.

an option if you prefer sticking mylar down is a vinyl cutter. You can make any shape you want with one of those.

I got a brother scanNcut for an experiment making the rotating stand up targets for Beat Time ... vinyl numbers stuck to new blank target and self-adhesive mylar disc over the top. Still looks new after a year of play. The mylar disc had a hole in the center to go around the target rivet.