TIG Calculator

The TIG calculator is intended as a print out reference for DIY TIG welders but is only intended as a starting point. Once you get the hang of TIG welding you might find you prefer to weld at higher or lower amps depending on technique and travel speed. Complete beginners might prefer to run maybe 10% lower amps to compensate for slower speed, but if you find you need to reduce amps much more then your arc gap is probably too long.

We've only covered up to 3mm in the chart. Beyond that thickness (apart from for specialist applications) you would tend to do multiple runs or just use TIG for the root weld and use Arc or MIG for filling in the remainder of the joint.

Mild Steel

Steel Thickness
(mm)
Filler Rod
(mm)
Tungsten
(mm)


Practice beads


Closed root butt joint


Fillet joint


Open root butt joint (gap is half of material thicknesss)


Lap joint


Outside corner joint

Amps
Amps
Amps
0.8
1.0
1.0 or 1.6 1
25
30
20
1.0
1.0
1.0 or 1.6 1
30
35
25
1.2
1.0
1.6
35
45
30
1.5
1.0
1.6
45
55
40
2.0
1.0 or 1.6 2
1.6
60
75
55
3.0
1.6
1.6
90
110
80

1 A 1.6mm tungsten is OK down to about 30 amps. It can be used on thinner material if the tip is kept very sharp. Reduce the amps a little if using a 1.0mm tungsten.

2 2mm is the transition between 1.0mm and 1.6mm filler rod. The larger filler rod cools the weld pool more than the smaller rod so you might add about 5 amps if using 1.6mm filler rod.

 

Stainless Steel

Stainless is less thermally conductive than mild steel, so heat does not flow away from the weld quite so quickly. The amps required to weld stainless are about 10% lower than the amps used for mild steel. Beginners might find the stainless chart handy for mild steel - the lower amps will compensate for a slower travel speed.

Steel Thickness
(mm)
Filler Rod
(mm)
Tungsten
(mm)


Practice beads


Closed root butt joint


Fillet joint


Open root butt joint (gap is half of material thicknesss)


Lap joint


Outside corner joint

Amps
Amps
Amps
0.8
1.0
1.0 or 1.6 1
20
25
20
1.0
1.0
1.0 or 1.6 1
25
35
25
1.2
1.0
1.6
35
40
30
1.5
1.0
1.6
40
50
35
2.0
1.0 or 1.6 2
1.6
55
70
50
3.0
1.6
1.6
80
100
75

1 A 1.6mm tungsten is OK down to about 30 amps. It can be used on thinner material if the tip is kept very sharp. Reduce the amps a little if using a 1.0mm tungsten.

2 2mm is the transition between 1.0mm and 1.6mm filler rod. The larger filler rod cools the weld pool more than the smaller rod so you might add about 5 amps if using 1.6mm filler rod.

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