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TIG welding basics


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Old 12-17-2007, 03:11 AM   #1
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Just bought a TIG machine? have no idea what you are doing? well read this!

First off, safety first, wear safety glasses, hot tig filler rod in your eye hurts! Yes, i have done this once...and NEVER again...cause it sucks

Equipment Needed: Welder capable of Tig welding, safety glasses, bottle of argon, CLEAN gloves, welding mask (I recommend self darkening but a conventional is ok), wire brushes*, tungsten electrodes(3/32"**), filler rods (3/32"**), bench grinder with at least 1 side dedicated to only tungsten (this is VERY important), cleaner or degreaser, clean rags, grinder

*You need to have different wire brushes for each metal that you are going to be welding. For example, if you plan to weld carbon steel and stainless steel you will need 2 different brushes. This is because any grindings or whatever can cross contaminate the weld. If you only plan on welding carbon steel, 1 brush is fine...i recommend spares though. Get small and large brushes. The brush needs to match the material!!!! you cannot use a steel wired brush on stainless...though you can do opposite =)

**Electrode and rod sizes usually coincide with each other...3/32" is a fairly popular size and will handle a decent current, as with any welding the smaller the material the smaller the electrode is needed.

TERMS:
DCEN (Direct Current Electrode Negative or straight polarity)
DCEP (Direct Current Electrode Positive or reverse polarity)
AC (Alternating Current)
Autogenous (fusing metal without using filler rod)
post flow (gas still coming out of the torch after the welding has stopped)
SCFM (Standard Cubic Feet per Minute)
Gas Cup (ceramic or glass part that diffuses that shielding gas and directs it to the puddle)

Before you connect the regulator to the bottle open the valve for a moment to blow any crap out of the threads, do the same before you hook the hose up to the welder.

There are many types of tungsten electrodes out there. 2% lanthiated is probably the easiest to learn on...It starts easy, and holds an arc well. It can be used for both DC and AC welding.

Turn the machine on, holding the torch in your hand, push the pedal down all the way for a few seconds, most machines come with a post flow set at about 12 seconds. You can now set your regulator, set flow to right about 20 SCFM.

Ok, now the machine is set up lets get the tungsten ready.

you want to grind the end of the tungsten to a point, some say dull some say sharp. I use sharp, and have had good results so far. Hold the tungsten parallel to the wheel and gently grind, twisting the electrode while doing this. you only want to grind about 2 times the diameter of the electrode, so taper well =). Insert it back into the torch, you can put it through the cup its easier than taking the electrode cover off every time, all ya gotta do is loosen the cover a few twists and it should slide right in and fall right out! you want the electrode to stick out no more than the diameter of the cup.

we are now ready to weld!

cleaning is KEY to making good tig welds. After you are done grinding and preparing your metal to weld you should hit it with some sort of cleaner or degreaser, one that doesn't leave a residue. To be sure, you can hit it with regular isopropyl alcohol. MAKE SURE IT IS DRY AND THE BOTTLE IS NOWHERE NEAR THE WELD. cause it will make fire...we are not biker billy, we do not want to cook with fire. hell, we don't even want to cook, we want to weld! Just a side note, wire wheels are the shit, but you have to follow the same guidelines as with a wire brush.

Set your machine to DCEN, and set the heat to about 125. MAKE SURE THE GAS IS ON! Grab some steel and practice starting the arc. Hold the electrode about 1/4 -3/8" above your work. If you are having trouble with this, touch the cup, not the electrode, to the work near where you want to start. Hold it at the same 30 angle as when you are welding. Push the pedal down some, and the arc should start. You can now start adjusting your current flow to the needs of your weld. The pedal will only provide the max current the machine is set for. I like to set it a little bit higher than what I will need because then I have the extra juice to make a quick spot melt if need be.

You should be able to see your puddle easily, it will look like a bit of mercury, go ahead and move it around, its pretty wild lol...Proper torch angle is about 30 from vertical away from the direction of the weld.

Most welding process move the puddle by making "c's". This is not true with tig welding. A tig puddle is advanced slowly by pushing. Move you puddle forward a tiny bit, stop, move forward, stop, move forward, you get the point . To make the puddle grow, move the torch in a circular motion this will heat a greater area, don't get too crazy or your puddle will get too big, and it will start cooling and make a mess. If you touch the electrode into the puddle you must stop and regrind the tip, you also must grind out that part of the weld because it is now contaminated...you will do this a lot at first...it sucks lol...The machine has a set post flow. This is to keep the gas shield around the molten metal until it cools and keeps it from getting contminated. Keep the torch in the same position after you stop your weld until the pool solidifies, this usually takes 2-3 seconds.

Now, if you have some filler rods handy, grab one. Proper entry into the puddle is about 15 above horizontal. Get your puddle going for a few seconds, once it is nice and fluid start moving it forward, dipping the rod in the FRONT of the puddle. You must keep your electrode in the gas shield in order to keep it from getting contaminated while molten. Move forward a tiny bit, stop, DIP, move forward a tiny bit, stop, DIP, got it...Probably not, its going to take a ton of practice, don't get discouraged let your failure motivate you! If you stick your electrode and filler rod into the puddle DO NOT let go of the electrode until the current is off you will get a shock, and if you are wearing crappy gloves you probably will scream like a woman...i use good gloves lol you should too! the lincolin electric gloves they sell at home depot are super!

Once you get your puddle moving you will notice you can back down on the current a little bit. This is because the puddle is doing some of the work for you, just like when you are using a cutting torch. The molten metal is releasing heat into the metal and preheating it and by the time the arc gets to it, it is pretty much at its melting temperature already!

You will find that you can weld most joints autogenous. Butt welds should have chamfers ground into them and filler used, as well as T welds and some lap welds. Most of the time it is up to the weldor though. Unless it is certified or designed work. Then the engineer gets to decide .

The above is just a very basic overview on what is needed to be done to tig weld. I highly recommend using this link to the Miller web site and downloading the TIG Handbook. Its free!

Miller - Education - TIG Handbook

I have a copy of it at work and read it a few times before starting to tig. I still use it for reference because it has excellent info in it, and lots of it too! If you are serious about learning how to tig weld you will download and read this book.

Few extras...

Being able to start the arc is made possible by a high frequency starter. If you have a machine that does not have this option, you will need to "scratch start" this is done by gently touching the metal. It is a pain in the assholes to get it right!

Tig welding aluminum is HARD don't expect to do it right off the cuff. Get good at metal first, then try aluminum...after 15 minutes of it you will say "**** it I dont need to weld aluminum anyway" lol . The best part is when you hold the torch angle a little too much and it starts blowing the arc out a little bit and melts the damn filler before it gets to the puddle...

Any questions just ask!


Last edited by lincolnmetal; 05-08-2008 at 09:49 PM..
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Old 12-17-2007, 05:46 AM   #2
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Damn good write-up. That's going to help when I start tig welding.

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Old 12-18-2007, 01:16 PM   #3
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Quote:
Originally Posted by lincolinmetal View Post
J
Being able to start the arc is made possible by a high frequency starter. If you have a machine that does not have this option, you will need to "scratch start" this is done by gently touching the metal. It is a pain in the assholes to get it right!
I just don't bother unless the machine has HF start. I love it.

Quote:
Originally Posted by lincolinmetal View Post
Tig welding aluminum is HARD don't expect to do it right off the cuff. Get good at metal first, then try aluminum...after 15 minutes of it you will say "**** it I dont need to weld aluminum anyway" lol .

I've had to pinch weld tubing a few times at work. We essentially flatten the end of the tube in an arbor press and fuse the seam shut. I agree, aluminum is hard to do.

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Old 12-18-2007, 05:22 PM   #4
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Quote:
Originally Posted by 98SS View Post
I agree, aluminum is hard to do.

agreed X 900,000,000,000

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Old 05-08-2008, 03:34 AM   #5
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ive done some tig here at school, my instructor used to work at lincoln for development,

for aluminum he said to go ahead and grind a point on the tungsten and run DC electrode positive (i believe, ill have to double check) until a ball forms on the end of your tungsten, then switch over to AC.

but i will agree on getting shocked, its not fun. i got it a couple times tonight where i didnt have my foot entirely off the pedal.


also, the high frequency start is cool when your not even close to your workpiece when you hit the pedal without your mask on, it has a neat faint bluish glow

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electrode, filler, gas, gtaw, tig, tig weld, tungsten, weld, welding


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