Yeah I used methyl-ethyl ketone from a rubber supplier. I knew that glue wouldn't hold. I thought about wrapping it with a thin strip of fiberglass and resin, but I never got around to trying that.
I can see what wualta is getting at with the screw idea, but I've tried that sort of thing with other broken plastic tubes. The trouble with that is you never get the pieces to mate perfectly when you're threading a screw between them unless they are in one piece or clamped together when you start - and the torque involved with driving the screw in will break the sort of bond that needs reinforcing.
Perhaps MEK is the wrong solvent for this stuff? I know a guy who used to do some sort of engineering at an injection molding factory, one of these days I'll pick his brain a bit.