Tig welding

I'm thinking about taking up some schooling this winter... I do a lot of welding and thought I would like to learn Tig welding... Whould anyone here explain what Tig welding is and how it works... Also ... Can a Mig weld do Tig welding with attachments??? Thanks... Kevin

Reply to
Kevin Beitz
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Reply to
JR North

TIG machines and MIG machines are very different. There are machines that can do both, but none that do both really well.

You can TIG weld off of any Stick welder, but if you want the full process you need a real TIG machine.

You don't need a big or fancy one, but a real TIG machine is set up for passing the shielding gas through the machine and allowing a foot pedal to control your power contactor and amperage level. Also a TIG machine will have a built in High Frequency transformer for initiating your arc.

TIG is basically striking and arc between the base metal and a non-consuming tungsten eletrode. A inert shielding gas is used to protect the tungsten and the molten puddle from air. The current is controlled by a foot pedal, and the filler rod is fed by hand just like gas welding.

Reply to
Ernie Leimkuhler

What keeps you from getting a nasty shock from the high freqency?

Reply to
Jim Stewart

The base metal is a better ground than you are, most of the time. Honestly everybody who TIG welds get bitten by high freq. a few times. No big deal. You jump out of your socks, but that is about it. High frequency electricity goes through your skin, not your heart. So it makes you jump, but does no damage.

I have been hit maybe 5 times in 20 years of TIG welding. Most of those times were when I was using a thumb-wheel controller instead of a foot pedal and forgot I had the power on.

Reply to
Ernie Leimkuhler

One can't do the other. Mig is constant current and tig is constant voltage, IIRC. With a tig you can also stick weld. Mig uses feed wire that acts as the electrode, melting as it is feed into the weld. Tig is just an inert gas sheilded arc that can do fusion welds where no filler is added or used with filler rods like A/O welding. I've used tig to do fusion welds on sheet metal that were less than 1/16" wide with 90% or better penetration. Unless you're into a production type situation tig is the way to go IMO. It produces the most beautiful welds, depending on operator skill, and is the most versatile and can weld the most number of materials. If I want to weld the occasional heavy piece I use the stick for that, not as convenient as mig, you have to chip the slag off and it makes a lot of smoke, but I don't do heavy stuff very often. Of course mig is by far the fastest and most common method of production welding.

I would get a real tig machine if you can afford it. They really do come in handy if you're halfway serious about metal working. Miller has a 25% down 0% interest deal going on now in which they will not only finance the machine itself but all the necessary assessories like tanks, helmet (get an autodark), regulator, etc.

John

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Reply to
John Flanagan

"Skin effect".

High frequency AC at megahertz frequencies (RF) does not travel "thru" conductors except at and near the surface. If you are the conductor, it travels on your skin but not thru the bulk of your body. The result is more like a burn than a shock. The HF in a TIG welder is very low power. When (not if) you get "bit" it's annoying enough to motivate you to wear gloves, but it doesn't jolt you like a sparkplug wire does.

Reply to
Don Foreman

I'll add another effect - though not normally seen.

"bone effect"

Low frequency AC at 40 or below HERTZ that is - 28 was the actual frequency the (AF) tunnels through a limb to the bone and travels down the marrow. It pops out at the exit point - burning the blood generation cells up.

This is one reason it wasn't used on Ships. To many demonstrations led to the ban. My Dad doesn't have marrow in his right forearm.

He was bumped into a generator and broke his fall with his arm...

He was into Ship and Air borne Radar - circa 194x in a Western Electric plant. I think the reason for 400 Hz in airplane is small transformers/inductors. Ships needed ballast anyway - and it was felt (likely true - never thought to much) that lower frequency was more efficient or something. Guess they stuck with

60 cycles/sec - Hz - like the ground forces.

Martin

Reply to
Eastburn

I knew that. Really. Dyslexics of the world, Untie! :^).

John

Please note that my return address is wrong due to the amount of junk email I get. So please respond to this message through the newsgroup.

Reply to
John Flanagan

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