Vectrex Joystick arcs

A fellow vectrex owner needed to repair the joystick in the controller. It turned out that one of the arcs had snapped and didn't work in one direction. We tried to glue it together again with a variety of glues and adhesives. The plastic that the original arcs are made of is slippery in itself, so not even slow setting industrial grade two component epoxy could stick to it for a prolonged period of time. Eventually it would just fall off and the fix would be unmade.
"Welding" the broken arc wi