John's Alu Profile build

[JAZZCNC]

I'd be very happy with that as a first welding attempt - nice one! But yeah MIG isn't going to be best for that material size - I'd be surprised if it has enough penetration.

What's the phrase? Grinder and paint make me the welder I ain't.

Mig is more than capable of welding that material, but 100A isn't. It would need 250-300A and thick wire. The trick with Mig is setting the wire feed correctly.

Also when your butting 2 pieces like you have if you grind a chamfer on each edge where you want the welds it will give you a stronger weld as you have larger weld area, it also gives you a flatter weld with hardly any grinding required.