You can TIG (heliarc) weld cast aluminum. Seen it done several times. I've had cast rims repaired (backside) and they held up fine.
Maybe I overstepped a little with my last post. Yes, you
CAN TIG weld cast aluminum. The frame on my Triumph Speed Triple is cast in a few different sections and welded together. But, unless you're talking about a machine weld on something that was intended to be welded, welding cast aluminum is NOT easy. Ive done it, and although my TIG machine isn't the latest and greatest out there, its not a piece of cake. The casting process entrains air and contaminants into the metal, which usually isn't the best alloy to begin with. Since aluminum welding is so sensitive to contaminants in the first place, it makes the weld harder to accomplish. The alloy itself makes a huge difference, the frame on my motorcycle is likely a MUCH different alloy than the Chinese cast YearOne wheels we're talking about. And the quality of the casting makes a big difference. Higher quality castings will be much easier to weld because they have less "junk" in them. But again, we're talking about cast alloy wheels that are likely made in China.
So yes, it can be done. I still wouldn't recommend it, and if you MUST have it done, make sure you find a shop with a welder that you really trust, because getting it wrong means a wheel failure down the road. With the amount of available wheels out there, I would just pick something that is made in the size you need, rather than messing with something that isn't.
