Mylar? I feel like this is my answer to everything recently. Haha

Scuffing up the surface of the target face so the adhesive has something to bite on helps...then mylar like above. The trick is not scuffing the edges where the decal doesn't cover.

I put a coat of varathane over the top (brushed on from a can). Added benefit is that you can aggressively clean the target face without affecting the decal. I've got machines that I did this to 5-6 years ago, and the drop targets look like they did the day I put the decals on.

Make sure to clean the targets well before applying new decals and always give them a good wipe with iso alcohol after cleaning and then apply decals. Should help.

The varathane hasn't yellowed over that time?

If you're talking about the edges peeling you can use either a sealitpen (acrylic clear coat) or 3M 3950 edge sealer (acrylic/vinyl solution in xylene--test to make sure the xylene won't damage the graphics). Both of these products are commonly used by professional decal installers.

https://www.amazon.com/sealitpen-Sealit-Pen/dp/B000FT56OQ

https://www.amazon.com/3M-Edge-Sealer-3950-Graphics/dp/B005LDH83S

These can also be used on cabinet decals.

I print the DT stickers on Avery Permanent sticker paper, then cover in Mylar.

Avery sticks better to glossy surface than rough, beware.

This is completely true. Almost all decals will adhere to a smooth surface better than a rough one. This is not paint we are talking about. I am a professional decal installer with almost 30 years under my belt. Trust me on this.

This will help with paper decals but not so much with vinyl. Vinyl ALWAYS shrinks over time after application. How much greatly depends on the material being used. Some a fair bit, other just slightly and once it shrinks, it will create a small gap between the edge seal and the vinyl rendering it pretty much useless. Seen it happen a million times.

In my experience, I must disagree. I have seen too many decals just peel away at the tops and bottoms because the adhesive had only a shiny-flat surface to stick to. I guess it's like backglass delamination. I've seen it over and over on those 80s WMS drop targets. Scuffing them up gives the adhesive little nooks and crannies to grab aholt of. Just my personal experience.

I agree to disagree. By scuffing it up, you are actually lessening the surface area the adhesive has to stick to. Every scratch you make when scuffing is an area that the adhesive will not touch but just float over. Unlike paint that will flow into them scratch channels creating a stronger bond, decal adhesive will not.

This is usually due to either poor quality and or old decals (even newly bought decals can be old) and the adhesive has dried up just a little (maybe not even enough to physically notice) or so often the target has not been cleaned properly beforehand. Wiping down after cleaning with iso alcohol makes a huge difference.

Heh...arguing about stickers...

I don't think the scratches are that deep The adhesive gets pressed into the scratches when you mount it.

I don't think anyone is arguing here. Just debating. . Like I said, I've been a professional sign and graphic installer for almost 30 years. Take it for what it's worth.

No. Varathane clear water-based polyurethane (or Minwax water-based polycrylic) doesn't yellow over time. Same stuff a lot of people have used for clearcoating playfields.

Yes, water based Varathane DOES yellow over time.

Just because it says "non-yellowing formula" on the can, does not mean it won't yellow, it will.

Here is a water based Varathane cleared playfield:

49bf2512d942e7d509e6ebc99f163e6aa69b4806 (resized).jpg

Here is where you scrape off the Varathane to see the true white paint underneath:

52b5f5e417aa5bbfaf70e57dc9daf2bdbd840f5d (resized).jpg

Don't let them lie to you, Varathane is garbage.

I have a related question:
The cabinet decal on the my IMVE is starting to lift on some of the edges. What is the best product / method to resecure without replacing the decal?
I have also noticed decal bubbling around the flipper buttons. Should I do something other than add mylar to this area?

Try removing the button (nut on the inside of the cab), then GENTLY warm the area with a hair dryer press the bubble out, towards the button hole.

Allow to cool, reinstall the button - DON'T OVER TIGHTEN the nut this time.

Pick up a can of 3M super77 spray glue at home depot. Spray some out onto something (inside of the lid wil work) and use something like a popsicle stick or toothpick if it is a really small corner and lightly coat the back of the decal where it has lifted and also on the cabinet. Wait about 5 mins and then squeegie it back down. Just make sure both sides are coated evenly and don't use too much.

I like the idea of painting on a protective coating that would seal the decal under it on targets, etc. Maybe the yellowing is dependent on UV exposure, and in any case, the risk of a yellowed target is not as serious as a complete playfield.

I've tried using Mylar in the past to seal target decals, but it never sticks well and always has little air bubbles under it. I live in a dry climate so maybe the mylar glue is dried out already.

Any suggestions for something (else) that can be brushed on to protect the decal and keep it sealed to the plastic?

Stick the Mylar to the decal before you apply it to the DT.

If you still somehow get an air bubble, Just poke it with the very tip of a safety pin.

DT stickers are going to wear, no matter what you do, so I would not worry too much about them, really

Thank you for the advice regarding the IMVE decals Superbee and Vid1900.
Much appreciated!