Plastics are difficult to repair. Most of the difficulty comes with properly identifying the plastic material itself. Having said that, I have had good results bonding some heavy duty drainage half pipe with a product called Professional Welder. It is a two part epoxy. The label list a bunch of stuff (Materials) its good for. You should be able to find it in some of the Walmart's & auto stores near the JB Weld. If not you can find it on Amazon & I think you can get it from the company direct. I got a deal on several packages on line, but can't recall if I got it on Amazon or the manufacturer. Also, I have had situations where I was able to create a lap joint in the broken part & then I used pop rivets to make the repair. If your not concerned about appearance, the rivets make the best repair & are the longest lasting in my opinion. Good luck with.Does anyone know what the best glue to use on the plastic guards and chute to fix cracks ?