TIG Welding GTAW (Gas Tungsten Arc Welding)

What is TIG welding ? It's a process for welding metals together using a tungsten arc.

An arc you say ?

An arc is created between two pieces of metal separated by an air gap, where the electrons manage to jump to the other piece by ionizing air, and thus creating a tremedous amount of heat in the process, which in turn melts the metals.

TIG parts

You have three main parts. The current transformer, the tungsten gas tank, the "torch". And of course the metal pieces you want to solder together.

What kind of metals can I solder with TIG ?

Steel, stainless steel, chromoly, aluminum, nickel alloys, magnesium, copper, brass, bronze, and even gold. source

Is tig the same as MIG ?

You must not confuse different types of welding:

Types of welding

• Stick
  • Description: uses a stick of the metal similar to what you are soldering and an outside coating called "flux". Both the stick and your piece are connected to two electrical clamps (one each). Bringing the stick and the piece close enough creates an arc. The flux burns off and leaves a coating on top of the weld (called "slag"), thus preventing air from contaminating your molten metal. This slag needs to be removed afterwards with a "chicken-hammer" (pointy hammer).
  • Pros
    • Inexpensive: ~ 100 USD
    • Good for structural things: trailers, furniture, bbq etc. Used very much in the pipeline industry
  • Cons
    • The slag that it leaves (not good for auto body sheet metals)
    • Not good for things thinner than ~ 1.5 mm
• Flux Core
  • Description: same physics as Stick welding, but different arrangement. Uses a motor to feed a thin flux core rod (your metal wrapping the flux) through the gun. The gun is also an electrical clamp, and you connect your piece are connected to a clamp as well.
  • Pros
    • Easy to use: the distance of your hand to the weld never changes (contrary to Stick welding)
    • Inexpensive: ~ 200 USD
    • Can use a MIG welder to do flux core
    • Good for sheets of metal up to ~ 4.5 mm. But there are heavy industrial equipments that use this techonology to weld very thik pieces.
  • Cons
    • The slag that it leaves
• MIG
  • Description: similar arrangement to Flux Core, but different physics (gas is used instead of flux to protect the weld). Uses a roll of wire coated in copper to protect it (ex: steel wire coated in copper), which is fed to a gun along with some gas (e.g. Argon or CO2).
    • Pros
      • No slag
      • Great all sorts of thickneses, from thin sheets to thick 9.5mm material (running on 240 V).
    • Cons
      • You need to have this protecting gas (argon, or carbon dyoxide)
      • More expensive because of the machines and the gas cylinder.
      • Less portable (gas cylinder)
• TIG
  • Description: (aka Gas Tungsten Arc Welding). Hybrid setup of stick welding and MIG welding. Instead of feeding the gun with wire, there is a non consumable Tungsten electrode that resits melting. This allows to concentrate lots of heat between your piece and the Tungsten tip, allowing you to slowly add melt a stick of metal that you feed with your other hand.
    • Pros
      • Most well controlled and precise of them all.
      • Ideal process for alluminum
      • Can be used to Stick weld
    • Cons
      • Most challenging to learn
      • You will need a machine that outputs AC and DC, that will increase the cost
      • Priced similarly to MIG with the AC options being in the higher end

TIG Equipment

1. Helmet, Miller Digital Elite.
   • Get one with an autodarkening feature
2. Gloves, Tillman
   • Really important, they must be heat resistant because the filler wire gets hot! Get ones that are made specifically for TIG welding
3. Tig finger (heat shield)
   • Nice accessory that prevents your pinky from burning when you rest it on the piece you are working on to support your slide
4. Welding Jacket
   • Nothing should jump on you, but the light is so intense that it will go through your clothes and sun burn you
5. Gas cylinder
   • To prevent oxygen from oxydizing your welds, TIG wraps your welding point (weld pool) with some gas (tipically Argon gas)
   • The cost of refill explained by the handling more than the gas itself, so having a big tank and a smaller handier tank can save you a few bucks
6. Regulators / Flow Meters
   • The Gas tank needs a valve, that you then connect to either your torch (if it has an integrated valve) or the machine itself (if you have a sonoid valve in your welding machine)
7. Tungsten electrodes
   • Color code telling you the chemical composition of the electrode. It's primarily Tungsten, but they are mixed with some other elements to keep the tip sharp for longer etc. The blue Lanthenated ones are good. The orange seriated electrodes are also ok.
   • Size 2/32" (2.38mm). If you do much much precision you can buy a smaller one.
8. Filler metals
   • Get the precut ones
   • Steel: ER70S2, ER70S6 (used for most work on steel) (1/16")
   • Stainless steel: 308L (most common stainless rod) (1/16")
   • Aluminum: ER4043 ER5356, if you are welding 6061 Aluminum, either of these will work. WARNING: if you are going to coat (Anodize) the aluminum don't use ER4043.
   • IMPORTANT: if you are doing a crytical application make sure you are using the right metal for the job.
   • NOTE: you can purchase a plastic filler metal bag that will isolate the metals from the environment.
9. Grinder
   • You will need to sharpen your Tungsten electrodes from time to time. Use a dedicated diamond wheel.