Originally Posted by RacerX
Welding isn't an option. If it were a steel rim, maybe. But aluminum is not repairable and neither is carbon fiber.
If it is cracked, it's broken and should be discarded. Just as a aluminum or carbon frame or other parts of the bicycle.
Some carbon fibre is repairable... Thermosets... no. Thermoplastics... yes. You can reweld aluminum too. You just need to be aware of the material. You will probably need to heat-treat it afterwards and of course machining will be required to get the surfaces smooth.