Hmmm, might work for a chip, but not certain about a crack. Car windscreens are done under pressure to make sure the resin properly penetrates the small cracks radiating out from the chip. A cracked windscreen, on the other hand, is always replaced – modern screens are a lot thinner than they used to be. I’m really not certain that a cracked phone screen could be fixed.
Still, it’s cheap enough to be worth a try, if only to extend the life of the screen for a few months or so. My phone has a screen protector on, which has got a couple of cracks across it, and chips around the edges, shows it’s doing its job.
