Introduction: How to Make a TIG Welder | Scratch Start

By The Eclectic Workshop
About: http://www.youtube.com/c/AndrewWorkshop

Tungsten Inert Gas (TIG) Welding is the ultimate in welding, it takes a lot of practice and you need specific welding equipment to do it well. It's more costly to get into than other welding processes. In this Instructables I'm going to show how I was able to make a simple TIG welder. This welder will only be able to weld mild or stainless steel but is a really inexpensive way to dip your toes in it to get some practice with the hand eye coordination needed to do TIG weld. To TIG weld aluminum an AC power source is needed as DC power can cause too much penetration and the AC power alternates the current to provide a cleaning action and there are other reasons that you can look up.

We call this type of TIG welder "Scratch Start" because to initiate the arc for welding, the electrode needs to be "scratched" or striked against the work piece to start. Expensive welding machines use either lift start or high frequency to initiate the arc. However there are times when even on the fancy welding machines scratch start is still used such as when welding on or around sensitive electronics.

Lastly with this type of setup, there is no foot peddle to control the power of the weld, this can be important as when you start welding the metal will start heating up and there is no way to turn down the amps to give precise control. The biggest cost to this setup is the bottle of argon.

Note: I do not recommend going out and buying everything to build your own TIG welder as the cost is better put towards a proper welder like a MIG welder but if you have an existing stick welder already it's worth trying this.

Step 1: Parts and Tools Needed

Here is what I used but there could be many other configurations

Tools

  • Bench or belt grinder
  • Thin welding gloves
  • Safety Glasses and welding Shield/Helmet
  • Leather jacket or other protective clothing for welding

Step 2: Assembly of the Parts

So the setup is fairly simple. The TIG torch will have a standard connector that will fit into most compact type welders like I have in the pictures. Connect the WP-17 Torch wire lead to the negative connector on the DC inverter welder. The ground clamp for the welder will be connected to the positive side instead of the negative.

This is called DCEN (direct current electrode negative), a setup like this results in less penetration but a higher deposition rate.

The argon regulator is then connected to the bottle of argon (the "IG" for Inert Gas in the acronym TIG). It is very important to use 100% argon, don't use any MIG welding gases like CO2 and argon, argon only. To the argon regulator connect the hose of the WP-17 torch, you might need to either find the proper fittings to connect it or cut off the existing fitting and fit the hose directly to the regulator using a barbed fitting.

The WP-17 torch might have an extra DIN connector or something similar you can just ignore that part, some welders can use that to control the start and stop but this welder set up will just have an always live torch.

Step 3: Sharpening the Tungsten

TIG welding involves using a non consumable electrode made from tungsten, hence the "T" in TIG welding. The size isn't too important as you can sharpen it to a nice sharp point or a duller point to give really precise control of the welding arc. I'm using 1/16" lanthanated tungsten, to sharpen them I chuck them in a drill and grind them on my belt grinder.

I cut the tungstens in half and sharpen them all so I have a bunch of pointy tipped electrodes ready to go. As when starting out to learning how to weld you will go through a ton of them, either by dipping the tungsten into the pool or burning them up.

After sharpening, the tungsten can be loaded into the torch, it's held in place using a collet, collet body and tightened down with the gas cup and the long back cap. The stick out of the tungsten from the end of the gas cup is calculated in 1/16 increments by the number of the gas cup:

So for a #5 cup = 5/16" stickout and a #16 cup = 1" stickout (16's of an inch). I went with a #5 cup as it's a good middle of the road size for playing around welding thin pieces of steel.

Step 4: Welding

Welding with a scratch start TIG is similar to stick welding, at least for starting the arc.

Steps are as followed for the first time when testing the welder:

  1. Load the sharpened tungsten into the welding torch.
  2. Open the bottle of argon and adjust the gas flow to between 10-20 CFH, adjust this as needed or you can calculate it with this formula: Gas flow is Gas Cup Number x 2 = CFH
  3. Turn on the DC welder, adjust the amps to 30 to 40 amps (adjust as needed).
  4. Attach the ground clamp to the work piece to be welded, I suggest just using a piece of scrap steel to test.
  5. Put on your safety equipment, position yourself in a comfortable position
  6. Turn on the gas valve to start the flow of gas to the torch head, you should hear it flowing. Hold the torch in the hand that feels the most comfortable.
  7. Lower your welding shield
  8. Pull the tip of the tungsten from left to right, or right to left, depending on if you are right or left handed. You want to be pushing the torch on a slight angle to push the weld puddle. This will take lots of practice but get comfortable with starting the arc and stopping.
  9. Practice, practice, practice. Change the tungsten if you dip it or if it burns up.

After being comfortable starting the arc, place a filler rod in the other hand and start feeding the rod into the weld puddle. This will take a lot of practice to get welds that look decent. You will notice that as you are welding you will have to increase your travel speed as the metal heats up. The other thing is you won't be able to do any post flow of argon on these welds to keep them shielded when you stop as you can't turn off the power to the torch head.

This is a really inexpensive way to try TIG welding and in capable steady hands can produce really nice looking welds. It's a really great way to practice with out spending a lot of money on a welder, provided you already have some of the parts.

Check out my video too: