"How long does Amazing Goop take to dry/set?"
It is kind of like silicone (except better) and so, normally, takes at least 24 hours to cure.

"What is Amazing Goop?"
Amazing Goop is a versatile adhesive and sealant that can be used for just about any do-it-yourself plumbing project. Use it to seal leaky pipes (non pressure types), downspouts, gutter seams and porcelain fixtures. You'll find it's even stronger than silicone on PVC tubing, pool tiles, and garden hoses. And because it dries to a waterproof, rubber-like consistency that's flexible, it won't break or crack under stress. Once you've tried it, you'll never stop finding uses for Amazing Goop. The only product that we see have more versatility is our "Ultimate Duct Tape."