Epoxy should work well. I use a brand called Supermend which is available at my local hardware store. It can also be plastic welded. I have a plastic welder designed specifically for welding radiators. If you took it to a plastic welder I would think they could do the repair in short order. Harbor Freight Tools sells a plastic welder for about $40. I bought one but haven't experimented with it yet to see how it compares to the one I bought designed just for radiators. You have to make sure your welding rods are of the same material as what you are welding.