[TheForge] Welding advice- carbon arc

[Howell Steve]

 Hi Ralph-
I have fond memories of carbon arc from my first real welding job; casting
repair on M-1 turbocharger housings. Contrary to what alot of people say
about it being nasty and noisy, I found that with proper travel speed,
amperage, etc. the process wasn't so bad. (then again- I like chop saws,
remember? ;)  Alot of the noise comes from the pecking motion some folks use
to scarf with. The arc struggles to maintain itself and then the compressed
air behind it gives it alot of 'pops and whooshes'. By running a tight arc,
kind of to the point of where you feel like you're jamming the electrode in
there, the noise is held down considerably. Works for me, anyways...
Of course, the spray is lovely to watch. The obvious saftey concerns should
be applied with the molten spray but with a graveyard shift full of 18-20
year old welders... let's just say that some were 'targeted' on occasion~
hee hee...
My God- if anyone can think of more trouble than that group... Acetylene
bombs out the back bay door, forklift races ... no wonder my mom thought I
wouldn't live to see 21! Me?  I never partook in the mayhem- honest!~

I made a compromise when I bought the Maxstar 200 Amp inverter and sold my
old 600lb workhorse Dial-Arc. Most importantly I gave up the AC that I could
have used dozens of times since then but I also lost the ability to use my
Air-Arc torch.  Running inverters with the process was highly discouraged by
the gurus at our local weld supplier. Like you said- for it to run decent
you need at least 300 amps and a healthy duty cycle. Maybe those with the
300 amp inverters would correct me but it sounded like that was frowned on
too. Could be a good reason to keep the old refrigerator sized machines!

PS-  I'll stop anoying everyone here in the near future with my security
tag.
in the meantime check out ballardforge.com.   I'm open for criticism, my
family already tore it apart so have at it~


Steve Howell
Seattle


>>>>


Andy,  The air arc process could be compared to a weld eraser.

It is a carbon graphite rod which is used as a non-transferable heating rod
element that uses compressed air from under the rod holder in the torch head
to remove the molten metal the arc from that rod is creating.  It is a
noisey, nasty process that requires proper safety gear be worn so you don't
get badly burned.

It is also very effective in removing welds with less heat transfer to the
base metal than a cutting torch.  The spatter and debris shoot 5-30 feet
away - so being aware of fire hazards is a good thing to be on top of as
well when doing this process.

It takes DC reverse polarity (electrode positive) with at least 200 amps for
a smaller sized electrode, but the most common size is 1/4, 5/16 for use
with the 400 amp torches.  Common current settings are 350-500 amps for
carbon arc gouging.  So, you need a good sized welder with a good duty cycle
to do this process.

There are also flat rods compared to the common round rods.  I've used them
to "sculpt" a block of metal like a carving chisel before.

Ralph


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