Plastic is really hard to fix. A new class of smart plastics can heal breaches all on their own, to mend cracked phone screens or stitch up airplane wings.

The aluminum roof has two plastic or acrylic skylights framed in aluminum, each 2 feet by 4 feet on the outside. One of the skylights cracked last month, and I am trying to get it replaced.

Fixing Small/Hairline Cracks A small crack (anything less than 1/4") is really straightforward to repair. You can fill the crack with premixed concrete crack filler that comes in tubes similar to ...