Question concerning Fast?
This can be fixed with epoxy. Take a small grinder with a rough disc. Gently grind out a small V into the cracked area. NOT all the way through. Mix up the two part epoxy with a spreader. Like for window tint or decals. Then fill in the grinded out area you made going through the crack. Try to get it really smooth and you will not have to sand it. Take your time.
I repair bumpers on car using this method. And you would be amazed at what I can fix. You could never tell and it is very durable.
Good luck.

