spektr wrote:

Richard.

The basic problem with Mig welders is the inability of the operators to set
them up.
As delivered, most home style 110 mig boxes are set up to use .035 wire.
The idea is to have a box for mild steel, cars trailers shovels etc......
Smaller wire
sizes are available and needed for thin wall applications. Use .023 instead
of .035.
Excuse me slaughtering exactly correct terms here, but the arc intensity is
a
function of the area of the wire. So heat control in BTU/Min is easier with
smaller diameters.
That means that the current carrying capacity of the smaller wire is 66% of
the .035 and
that go's a very long way towards making the job work.

For good fusion, the larger wire needs a btu/sec heat rate that in many
cases exceeds
the base metals "pour point" or the point where id is completely liquid and
flows away
from the weld. Using smaller wire gets the heat rate more in line with the
tubes fusion heat rate.

Scott Correa


Yep.
And there in lies the rub, at least according to the old timers.
That tiny intensly heated bead can lock in strong stresses.
Which suggests post weldeding stress relief (old argument).

With a neutral flame...

I bought a Hobart 135 to build my shop.
Later sold it for more than I paid for it (because it had a
new roll of wire on it at the time and bought my O/A rig
for working on the Tailwind.

Each has merits.
Could probably justify both if you have the pockets.

But I prefer the torch for welding thin wall stuff.

Richard