X2 on the JB weld. BUT, you must bevel the remaining plastic to create a wider (rough) surface for the epoxy to adhere to. I just did a butt joint and used the JB to recreate the whole tab (was completely missing). lasted about a year. it is on my list to redo and I think I am going to use some fiberglass window screening to reinforce the jbweld.
I've had very good results on plastics with using a screen support as described above.
JB is great epoxy. I use the JB cold weld on a 4" stress crack that I drilled stopped above a freeze out plug in my 396 block (apparently previous owner didn't use correct antifreeze levels) 25 years ago and it still is there and no leaks today.