Originally Posted by
peteeng
Hello Felix - I used to teach TIG welding many years ago. For the router you need to use tight fits, no gaps. A gap will allow the joint to shrink and distort. So make the fits as best as you can. For a router the joints do not need to be very strong so you do not need to do full penetration welds. For 4mm thick steel I'd be using a 1.6mm or 2.3mm tungsten. I would try to move along quite fast using a 2.3mm wire or even a 1.6mm but you would have to be quick. As a learner set up the cup so it rests on the job but the tungsten does not, this will prevent you from stubbing the tungsten, common for learners. ie you drag the cup along the surface. Once you get stronger and steadier you can then hold the torch in air. You want a short arc. You also want to linish the metal clean before you weld. Any dirt grease or paint upsets a tig arc very easily. Use a pointed tungsten and keep it clean. Use good gloves so you don't burn yourself and use long heavy sleeves so you don't burn your arms ( I have scars to attest to that one). Plus use sunscreen as the arc will give you sunburn as well. Or cover up really well. Practice makes perfect...
One thing you can try is tig brazing with a bronze rod. You don't actually melt the parent which is an advantage when learning and also means the distortion of the weld is very much reduced. If I was to build a steel frame or steel parts for a router I would torch braze or tig braze for this reason. I oxy torch braze this sort of thing these days to minimise distortion and stress relieve as it goes. Peter