I foolishly tried to triple thick a HG b/g a few years ago because one tiny flaking spot suddenly appeared on an otherwise perfect b/g. (OCD issues!)

But it gets worse. I decided to use painters tape in the four scoring windows instead of the tiny pieces of cardboard. Needless to say things went horribly wrong when I peeled off the tape after the Triple thick dried. Luckily the guy I bought the game from had an extra b/g. 150 mile round trip ride to NH and 125 dollars later (a bargain compared to today's prices) I had another perfect b/g again. Never use painters tape!