I believe it's good quality aluminum, not pot metal.
Aluminum can be brazed with the right flux and special fillers, see below. For that matter, there are also fillers for pot metal, but they are harder to find.
MIG welding aluminum can be done, but is tricky. Most MIG setups aren't really configured for it and it would be hard to get a good weld on your first attempt.
TIG welding is a better choice but you do need a rig that has AC settings. Some say it's harder to learn than MIG but I learned on a Oxy/Acetylene rig, so I had no trouble switching to TIG. I've TIG welded aluminum, thick metal isn't bad but thin material is easy to blow through. Both TIG and MIG require 100% Argon shielding gas.
There are some really good epoxies, JBWeld is the king of strength, but that means it's also somewhat brittle. Like any of these processes, surface prep is key.
That fact that this tab has broken off indicates that there is some stress happening to that corner of the part, either though over tightening of a fastener or repeated vibration so I'd think that an epoxy would also fail in time.
I'd think that either going with brazing or paying a pro welder to reattach the tab would be the best repair choices.
From a 'net search:
Key Aspects of Brazing Aluminum:
- Process: Unlike welding, you do not melt the base aluminum. The rod melts at a lower temperature, around 900°, and flows into the joint.
- Preparation: Thoroughly clean the surface to remove oxide layers using a stainless wire brush.
- Flux: Specialized aluminum brazing flux is essential to break down the surface oxidation.
- Heat Control: Evenly heat the base metal, not just the rod, to prevent overheating or incomplete flow.
Common Applications:
- Repairing aluminum AC lines.
- Joining thin aluminum pieces.
- Repairing aluminum castings or boat hulls.
Limitations:
- Brazed joints are not typically as strong as welded joints.
- The flux used can be corrosive, so cleaning after brazing is important.
For reliable results, popular options include filler rods like Lumiweld, Technoweld, or AL718.
