I believe the product is called Triple Thick. As suggested by Clay H.. You may still be able to find the info at Pinrepair.com

The link is not working.

Here is Clays guide.

http://www.pinrepair.com/restore/index1.htm#bg

No problem. Maybe we will meet up some day....MiPinball Expo?

If that BG is really in great shape, I would leave it. Triple thick coating etc. is a *stop leak" fix so to speak, not a preventive measure. I would just use lower heat producing bulbs and keep it in an area where it won't experience wide temp changes.

Sealing with Kylon Triple Thick is only necessary if you have any lifting of the paint due to moisture, bulb heat, etc.. If you have scratches or other defects where the paint is not lifting or if your backglass just doesn't have any problems, don't seal it. You may cause more harm than good.

If you do seal it, Wal Mart and other stores carry Triple Thick. Since Krylon makes so many different products you have to make sure you get the right one. Ask for Triple-Thick 0500.

Do not clean your backglass. Lay your glass on the floor. Cut up card stock, playing cards etc., to the shape of the score reel windows and credit window. I cut mine slightly smaller than the painted area. Place weights such as quarters, etc., to hold the cut-outs in place. Apply a uniformally heavy 1st coat of triple-thick starting at the top with your can about 6 inches away from the glass. Use left to right sweeping motions and work towards the bottom. This 1st heavy coat "sets" the paint chips that have lifted and bonds them to the product which stops the flaking process. Apply 2 more lighter coats reversing direction each time you spray your glass. Let dry at least 24 hours before you touch-up with paint. Seal your touch-ups with triple-thick when you're done. I spray some in the cap and use a q-tip for small touch-ups.

This is just how I do it. Everyone has their own way.........

http://www.amazon.com/Krylon-12-Ounce-Triple-Thick-Aerosol/dp/B001144TJC/ref=sr_1_1

Leave it. Triple thick is like playing Russian Roulette with a can. About 5% of the time you can Kiss a backglass good bye. Always only use it if necessary. I still use it but much less then I have in the past.

Plus after about 15 years the stuff gets really "brittle" and will crack.

The sad part is this stuff has become mainstream restoration techniques but if you have restored 100's of games you finally realize when and when not to use it.

It is good you asked.

I've only seen this once on my Blackout, but sometime in the past someone took a sheet of mylar and applied it to the backside of the backglass. No way to ever get it off without total disaster I'm sure, but it has held up great, looks like new. Not reccommending this method, just passing on random info.

Here is a picture of the backglass of my Abra Ca Dabra. It has a Mac-tac film on it. Fancy privacy film. When I bought the pin, I did not check the backside of the glass. I did check everything else. I have carefully looked at the front of the glass. There were no flakes, or paint missing. So I am not sure why this was done. It was most likely put on there some time in the 1980's. When I finally went to put new bulbs in. I had a WTF kind of moment. LOL.DSCN0379.JPG

There will no removing this film. I am sure that the paint will be pulled off too.