How about abs cement? Seems to really hold on abs plumbing parts. You could try a very small test area first. Then after glued back together use a strip of fibreglass cloth or simular glued to inside with abs cement to reinforce repair. Think it only comes in yellow around here though. If it is that waxey type of plastic polypropolene or whatever it's called that gas jugs are molded from then welding is the only option. I have never found anything that rebonds it.