You'd be wrong then because MIG is as good a process as any of the
others.
It's the easiest to do but it does have a downside and you found out
what
that is. One can make welds that look great but in reality they are
nothing
but glued together metal. If I recall they call them cold welds.
Penetration
is vital to a proper weld. A MIG welder will do whatever you want just
about
but you have to set the machine properly or your welds are no good. The
guidelines on the machines are a good starting place but every welder
that I
know of that uses MIG always does some test welds on metal like he's
going
to weld. Once you test your machine settings on similar metal of the
same
gauge as your project you will be fine. Someone once said that a chimp
could
MIG weld. But the caveat was that a human had to set the machine up for
it
first. MIG is all about getting the right settings on your welder. Once
you
have them right the welding is a breeze.

Hawke

Good point! When in doubt I always do some practice welds with
similar (scrap) metal in similar configuration to see what settings
are gonna work. It doesn't take long to discover what works with
the "usual stuff": flats, angle, channel and tube of thickness from
1/8" to 1/4" with some round bars now and then.


So, you make practice welds, and then you try to break them, is that
right?

There are a number of ways to test welds. Destructive testing is one of
them. Then there is X-raying them. There are also guys with the occupation
of weld inspector. They go to the job sites where workers are welding and
they have to certify them as safe or they don't pass inspection. I don't
know how they are able to determine the quality of welds but they can do it.
You could always find one of these guys and have him inspect your welds. Of
course, that's a lot easier said than done as they generally expect to be
paid for their services.

Hawke