Bet the instructor just copied it from an old textbook and nobody ever double checked the source.

Actually wait, your teacher might have been talking about regular school PVA which is definitely brittle. The Lineco stuff is a different beast, it's a modified PVA that stays flexible even after curing. I made that same mistake with a cheap Elmer's type glue on my first few repairs and watched them crack within a year. But the pH neutral PVA from Lineco is actually what most professional binders use now. Have you tested it on a spine that gets opened a lot yet?

My buddy Mike took his old Ford Focus to one of those mechanic-turned-financial-advisor types last year. @amy302 you are spot on because Mike ended up with a bunch of debt from bad stock picks the guy recommended and the car still had a broken alternator after all that. He spent like three months trying to dig himself out of that hole and the shop had to get a real tech to fix the car in the end. Sometimes people just need to know their lane, you know?

Hold up, 100 installs through old plaster? Bro, that's actual nightmare fuel right there. I'd have tapped out after the first ten with how brittle that stuff gets when you're fishing wires. Mad respect for sticking with it that long.

The 8% number hit me hard too when I first saw it. I started using blended cements with fly ash or slag for my own projects and it cuts emissions by like 30-40%. It's not a total fix but it's something we can do right now without waiting for new tech.