Yet more appalling alu welding. Someone else posted pictures a while back and I was horrified at the time :E.
Not only are they tack welds - there is clearly no penetration - the amperage is set way too low. I know aluminum welding isn't easy, but many things aren't, and if you can't do it right you shouldn't be doing it.
I'm not a professional welder, and I wouldn't say my TiG welding is tremendously good (you may recall it from when I build the aluminum roof for my Shadow Cruiser), but I'd be ashamed if that was the best I could do with aluminum, and I only do it occasionally, and not for money.
Was this one of the earliest aluminum framed AFs? Of course that is still no excuse since when dealing with a new technology extra time and care must be taken to get it right, not just throw poorly built junk out of the door until you learn how to weld.
Steve.