On Sun, 27 Jun 2010 15:34:44 -0400, "Ed Huntress"
wrote:


"Tim Wescott" wrote in message
...
On 06/27/2010 08:46 AM, JR North wrote:
(top posting fixed)
On Sun, 27 Jun 2010 08:45:07 -0500,
wrote:


I'm getting close to cutting out rust and installing panels. I have a
Century wire feed welder, MIG and flux-core, will flux core work for
auto
body? I'm wondering since I don't use this very much I took my cylinder
back instead of paying monthly rental. I can do a cylinder lease if
necessary but if Flux core wire will work for auto body repairs then I
can
save some money.

(compressor stuff snipped)


You can use the flux welder for plug welds; that's about it. Won't
work for panel butt welds or lap joining, except maybe to spot weld
the joints. It's almost impossible to run a seam in thin sheet metal
with a flux welder. You really need to Tig it.
JR
Dweller in the cellar

Or hammer weld it with oxy-acetylene. Not that this is a trivial skill --
it may take you less time to get a part-time job at McDonalds & save up
for a TIG welder than it would take you to learn how to hammer weld a
really good seam with oxy-acetylene. But it can be done.

I haven't seen that done for 30 years, but someone who was expert at it
tried to teach me once upon a time. He largely failed, or I just failed to
learn. d8-)

It takes a lot of practice and a fine feel to know how much to "splash" the
metal toward the weld with hammer and dolly.

I thought this was a lost art, and that everyone did this work with MIG
these days, hammering down the bead a bit and then just grinding it off? It
introduces a lot less total heat than TIG, and a great deal less than O/A.

The excess heat and consequent distortion is the problem with O/A. I
can do hammer welding, or could at one time, but MIG and TIG make life
so much simpler.