Greetings all:
I've read Richard Finch's book on welding, and actually have been welding
for many years, but one thing still gives me a problem. When I TIG weld
mild steel, my welds sort of "foam up." I'm using argon as the sheilding
gas, and I've tried increasing the flow, larger and smaller cups on the TIG
torch, and using both thoriated and non-thoriated electrodes. I use
high-quality certified welding rods. I've tried welding slower to keep the
argon over the weld longer, but no luck. This happens mostly when I'm
welding thick 1/4 inch material. Everything is clean. No drafts to blow the
argon off he weld. Tried both DC electrode negative, positive and AC.
What am I doing wrong?
Thanks for all. You can even flame me if you like. I like it.
JM
Somehow your gas is not getting to the torch.
Check your hoses and fittings to make sure you aren't sucking air in
along the way.
Make sure you are holding your torch in close.
If you are using a standard collet body you can extend the tungsten 3
diameters past the edge of the cup.
3/32" x 3 = 9/32"
Make sure all firescale is ground off the metal.
The steel must be clean.
No paint, oil, rust, scale, glue, whatever.
Make sure your filler rods are clean.
: :> Greetings all:
:>
:> I've read Richard Finch's book on welding, and actually have been welding
:> for many years, but one thing still gives me a problem. When I TIG weld
:> mild steel, my welds sort of "foam up." I'm using argon as the sheilding
:> gas, and I've tried increasing the flow, larger and smaller cups on the TIG
:> torch, and using both thoriated and non-thoriated electrodes. I use
:> high-quality certified welding rods. I've tried welding slower to keep the
:> argon over the weld longer, but no luck. This happens mostly when I'm
:> welding thick 1/4 inch material. Everything is clean. No drafts to blow the
:> argon off he weld. Tried both DC electrode negative, positive and AC.
:>
:> What am I doing wrong?
:>
:> Thanks for all. You can even flame me if you like. I like it.
:>
:>
:> JM
: Oh yeah, it could just be a bad bottle of gas.
: It has happened twice to me in 10 years.
: It can drive you nuts until you figure out it is the gas.
In message , John Magnus
writes
Hi Magnus,make sure you are using the correct filler.The filler rod for
gas welding mild steel is not suitable for TIG welding,it leads to large
amounts of porosity in the weld metal.TIG welding filler has larger
amounts of deoxidants.
Actually, you probably have ER70S-6. The "E" part means it can be an electrode
and the "R" part means it can be a feeder rod. Only McGyver could use 36" cut
rods in a MIG but it's ok to use MIG wire off the roll for TIG.
Note: Not that you were going to, but for reference, don't try this with flux
cored wire. You'll notice flux cored wire does not have the "R" part in the
class name. It's usually something like E71T-GS. The "T" meaning tube.
I don't know. I haven't got a TIG of my own or else I'm sure I would have tried
it by now. I've tried using 16penny nails in the stick welder. It was no fun at
all. ;^)
Thanks all for the advice. I bought some E75 rods today and tried them; I
saw some improvement, but still some foaming. I was a little annoyed that
the welding shop only had copper coated rods, as Finch's book suggests
avoiding them.
I've turned the argon flow rate so high that I know I'm wasting it. On a
guess, I tried using a non-thoriated, pure tungsten electrode and the welds
look much better. I also tested another theory by deliberately plunging the
thoriated electrode into the weld puddle. I noticed it exacerbated the
foaming noticeably, and when I re-ground the electrode, the foaming was
less. With the contaminated electrode, near the end of the weld, as I
stopped the arc and during the afterflow, the puddle actually foamed up to
form a little peak until it solidified.
I don't know the basis for this, as I've read that thoriated electrodes
are supposed to be used when welding steel, and pure tungsten used when
welding aluminum.
Any ideas why this is working or has anyone noticed a similar effect?
Thanks,
John
I have done it with dual shield hardfacing wire.
It is a bit messy, but works.
The problem is the sodium flare from the flux is quite bright in the
TIG arc.
Hmmm. That's news to me. Since TIG uses an inert gas atmosphere
while oxyacetylene welding does not, the need for deoxidants should
be *less* with the TIG process. I've used RG45 for years in both O/A
and TIG welding.
Gary
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