I did a little demo to illustrate the effect arc length has for someone struggling with a fillet weld recently. Thought it may be helpful for anyone new to TIG...
3mm mild steel, 100A, 1 sec slope down, 5L/min argon with a #7 gas lens. After tacking the bits together i added a couple of autogenous tacks using different arc lengths- on the right arc length around 1 - 2mm, on the left had around 5 - 6mm arc length. Too far away to get fusion
Ran short welds keeping the same arc lengths. With a long arc you initially get 2 puddles (unless the juice is cranked way up), adding filler fixes that but the puddle remains crescent shaped. The filler starts to melt before it reaches the puddle and tends to 'wick' towards one side or the other rather than where you aim. Obviously there is a large lack of fusion problem with the long arc weld
Despite staying at 100A the back of the piece (left and right obviously reversed) shows the differences in heat input
3mm mild steel, 100A, 1 sec slope down, 5L/min argon with a #7 gas lens. After tacking the bits together i added a couple of autogenous tacks using different arc lengths- on the right arc length around 1 - 2mm, on the left had around 5 - 6mm arc length. Too far away to get fusion
Ran short welds keeping the same arc lengths. With a long arc you initially get 2 puddles (unless the juice is cranked way up), adding filler fixes that but the puddle remains crescent shaped. The filler starts to melt before it reaches the puddle and tends to 'wick' towards one side or the other rather than where you aim. Obviously there is a large lack of fusion problem with the long arc weld
Despite staying at 100A the back of the piece (left and right obviously reversed) shows the differences in heat input