Dry aging in a spare cooler?" That's wild, I never even thought of trying that. How do you keep the temp and airflow right without it turning into a science experiment?

Just buy a new one cheaper than fixing it.

The temperature shock is what probably got it. When you go from a warm chimney back into a cold truck bed then back up to a hot flue, the poly expands and contracts fast. I bet the plastic got brittle from that cycling more than a few times. My buddy had the same thing happen and he realized he was leaving his brush sitting in direct sunlight on the dash all summer. Polyproylene degrades in UV light way faster than people think. Check if yours was stored anywhere near a window or in the sun for long stretches.

PVA is not all the same. You probably used a school-grade PVA, not a bookbinding PVA. The cheap stuff dries hard and brittle. Bookbinders use EVA or pH-neutral PVA that stays flexible. Wheat paste does have real advantages though. It stays reversible way longer. PVA gets almost impossible to undo after a few years. Wheat paste also doesnt shrink as much as PVA does when it dries. The trick is knowing which PVA you actually bought. If it says "school glue" or "craft glue", thats your problem. Real bookbinding PVA costs more than $15 but lasts decades without cracking.

Went STRAIGHT past the church part and got stuck on Detroit for a second. That city's got old buildings that eat signals like candy. I had a job at this old brick warehouse near Eastern Market, wireless panel couldn't hold a connection for more than ten minutes. Ended up drilling through THREE layers of brick and some kind of metal mesh inside the walls. Hardwired everything and it's been solid for a year now.