Learn How to TIG Weld Two Joints With One Easy Setup

Get off flat plate and start learning how to TIG weld. This beginner TIG lesson will show you how to weld two joints (outside corner and inside corner) and let you practice three welding positions (flat, horizontal, and vertical) in one simple build that's fast and easy to setup.

welding project for training, a simple box with inside and outside corners to weld

Pros & Cons of Learning on a Flat Plate

Learning the very basics of TIG welding on a flat plate is nice. Our intro articles start there. You can learn how to see the puddle and move the torch with beginner TIG drills. And you can avoid common beginner mistakes by learning about the core variables, like arc length and torch angle. But flat plate has some big problems. For one, it's actually HARDER to weld on a flat plate than in a weld joint!

Fast to prep  No visual cues to follow
Lots of weld time Puddle is harder to see
Cheap for schools on large scale Boring 

It's a good idea to get onto real weld joints as soon as you get the basics down; and with the setup shown in this article, you'll be able to get a ton of weld time on real joints with little time wasted on prep. 


  • Materials 
  • 4 ways to mark metal
  • 2 ways to cut metal
  • How to prep
  • Fit-up and tacking
  • Outside corner first pass (root)
    • Laywire vs
    • Dabs 
  • Outside corner cover pass(es)
  • Inside corner (horizontal position)
  • Inside corner (vertical position)
  • The finished project. What the heck is it?
  • Troubleshooting 
    • Beginner mistakes on outside corners 


Four equally sized pieces of 1/4" thick mild steel.  Here I'm using the 2" wide by 6" long (finished) plates from lesson one and two. A TIG welding machine. And an angle grinder.  That's it. 

4 Ways to Mark Metal 

From left to right: sharpie, soap stone, silver streak, metal scribe.  The scribe shows up best while welding but is hardest to see during layout and fab.

2 Ways to Cut Metal

(Left, Above) Chop saw cutting metal plate. (Right, Above) Angle grinder with skinny wheel cutting metal plate.  Both work, the only difference in the final product is the chop saw has wider kerf.  The table below highlights some differences in practice. 

Chop Saw Angle Grinder 
Easy to get straight cuts Need practice to get straight cuts
Less skill needed Versatile when mastered

More expensive


Metal sizes and thickness limited

Wider range of size/shape/thickness

How to Prep Metal for TIG

I like to use a flapper wheel on an angle grinder to prep metal for tig welding. It's fast and smooth and gets great results.  For mild steel, like here, remove all the mill scale on each metal edge (this will be the surface of your outside corner welds), as well as a little back on each face until it's shiny silver. 

Fit-up and Tacking

Fit your pieces up for two 90 degree corners, each with an open groove on the outside corner to weld. Touch the edges of the plates together before tacking (don't overlay them).  I like to use a simple angle iron jig for this (see pic below).



Outside Corner First Pass (root)

The weld puddle image above is from the lay-wire method. I'm holding the filler rod down against the outside corner groove and running it over with the weld puddle (120 amps with 1/16" 70S-6 filler rod).


(Left, Above) shows my torch position. (Right, Above) shows how the filler rod is pressed down into the groove. 


Lay-Wire vs Dabs 

(Left, Above) lay-wire root. (Right, Above) dabs. Both at 120amps with 1/16" 70S-6 filler.  Since the first pass here isn't an OPEN root, it doesn't matter which way you weld it.  Try both and see which you like better. 

Outside Corner Cover Pass(es)

After you put the root in, you want the next pass to cover the prior weld completely and fuse into each bevel edge. You want the weld to remain flat, so don't wash the puddle all the way up to the corner of the edge. The idea is to barely overlap the prior weld and fuse it into the base metal. You can put more than one pass, fill the entire groove, and even cap it, but it's the same idea for each new pass. Just barely overlap the edges of the weld underneath.

(Left, Above) The arc has just been struck, you can see the root pass is already welded, which we are about to cover with a new weld. (Right, Above) The molten weld puddle is covering the root pass and fusing into the sides of the outside corner bevel.  If you compare the two pictures you can see how much the cover pass is overlapping the sides of the weld beneath. 120 amps, 3/32" filler rod.  When first learning you might be better off running around 105 amps to have more control over the puddle.  It's not a race. 

Inside Corner (Horizontal Position) 

Weld positions are defined by the direction of the weld. (Above) You can see the setup for an inside corner weld in the horizontal position.  When dealing with horizontal gravity plays a roll, pulling the puddle down towards the bottom toe, but it's not something to focus on too much. Angle the tig torch into the center of the joint, slightly favoring the upper side. The weld puddle follows heat. Where the arc points is more powerful than gravity. 

 The main thing is to get comfortable. Pull the puddle towards you and find a position where you're able to see the weld (as shown above). The nice thing is you can put as many passes as you want on the inside corner, as long as the base metal is prepped back far enough.

Inside Corner (Vertical Position)

Once you're done with your first two inside and outside corners, tack the two sides into a box (shown below).

You can weld the outside corners in any position you want, flat like the first two, horizontal, or even vertical. But when it comes to those last two inside corners, you have a perfect setup to practice a tricky vertical pass (image below). This is type of thing you'll encounter when building stuff and fabricating. This training setup gives you a chance to practice trickier stuff, or at least get some controlled exposure to it, before welding on projects.



The Finished...Thing...What is it?

The goal here is a training piece. If you've been following along from the prior two lessons, you can use those plates and get more welding out of them. But this basic box has a use. It may not be much, but it makes a perfect cup holder.  Nothing worse than knocking over a drink on your fab table or desk. Not going to happen with this bad boy (pic below).



My brother is learning to TIG weld and worked through half the welds of this training build.  The outside corner weld (above) on the cup holder is one of his.  Not bad!  I'm a professional welder, but by having him go through the exercises we're able to show some real world examples of the types of little mistakes beginners tend to make and how to prevent them. 

 (Left, Above) Beginner outside corner.  Problem: The arrows point to "pecker tracks," where the weld was washed too far forward with each step, leaving small gaps between the weld toes. The edges of the weld should form a straight line along each side. Solution: We lowered the amps down from 120 to 105. This allowed for a smaller and more controlled puddle, which he was able to wash forward in smaller steps and align each weld edge up with the one behind.

 (Left, Above) Beginner tig weld. (Right, Above) Professional tig weld. Problem: Two things are going on here. First, the weld is going too far up the side and crossing over the corner edge.  You want to leave those top corners in tact unless you are putting a cap on. Second, there's some undercut. Solution: Lower amps from 120 down to 105 to have better control of how far the weld is moved to the sides. Tighten the arc length to prevent undercut. 


As soon as you are able to move the puddle along on flat plate without dipping your tungsten or melting the filler rod back, get onto some real weld joints.  The training project here is fast to setup, gives lots of weld time, and can be repeated as many times as you want. 

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