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Jay
03-18-1999 21:05:14
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Re: Re: Re: Re: Re: Re: question on oxy-acet welding in reply to Jim WI, 02-22-1999 11:04:50
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I am a pro and I will try to describe the different ways to oxy acetylene weld. On cast iron, you can get too hot too soon by spending
too much time getting the metal "cherry red."
Use either a flux coated brass rod, or preheat the bare rod and get as much flux as poss stuck
on to avoid stopping to re-dip as much. start
applying the rod as the metal begins to glow, but
manage the heat to avoid heating beyond the range
of the flux to avoid oxidizing. the brass will
"flow" onto the joint and "bond" with the base
metal rather than bead up. The same goes for steel, but steel will tolerate more heat before
oxidation keeps the brass from flowing. As far as
"puddling" steel goes with baling wire, this works better when joining edges, there is no fool-
proof method of welding in the middle of a section of sheet without major distorsion. A pro
body man would use a special lead solder to fill
holes in sheet using as low a heat as poss. this
is done every day on the assembly line at any of
the auto plants, on the joint between the roof
and the pillars, so it can be bought with some
calling around. mig guns can be used on sheet, but after much fiddling with heat, feed, and wire
diameters on scrap pieces. tig machines are the best thing to use on sheet metal, but they are
expensive. there are "exciter" boxes that can be
added to arc welders to get around much of the
expense that converts them to tig. tig is better
on thin material because it is somewhat like
puddling with a torch, but you don't have the distorsion of a torch because you are basically
substituting the flame for an arc, which is shielded by the argon gas, and the heat is contained in a smaller area. A good tig man can
take two metals that normally are not candidates
for welding, and join them simply by puddling
with the tig arc, such as brass, bronze, and pot metal. even if a filler rod is not available.
Good Luck
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