"SteveB" wrote in message
news:zHOpe.9224$tr.3343@fed1read03...

"Jim Newell" wrote in message
...
I have been practicing welding with my MIG. I think I am getting good
welds. I beat on them, and they don't seem to break.

What I am bugged about is the "fit and finish" of the process. I see
sites that show different welds, and they look great. For example I saw
a Ducati motorcycle frame that claimed to be MIG welded, and it was
superb....apparently no grinding or other cleanup.

Is it just a lack of skill on my part, or is there always a ton of
cleanup, grinding, etc...to get a nice looking fit and finish?


Remember that a lot of those welds are done by robots. I can get
beyootiful welds with my MIG, and then, a real groaner. These are
identical welds like repetitious welds when welding wrought iron.

There are some things that robotic welding has over humans. They travel
at an exact speed. On starting a weld, they may have a pause time, or may
even be moving before the arc is struck. When everything is right, higher
heat can be used with less chance of burnthrough. Rule is that the better
a weldor is, the higher heat he can run on the same materials with the
same rod.

But I do agree with you. I see some welds of manufactured goods, and
wonder, "How'd they do that?"

Steve
A lot of people think MIG welds should look like the "stack of nickels"
characteristic of stick welding. Robots can be programmed with a slight
whipping action but I have read that doing this manually may result in a
lack of root fusion. Maybe the robots are creating a nice convex bead with
freeze lines. It seems like even a perfect straight manual MIG weld does not
have the aesthetic appeal of a nicely done stick bead.