A couple things I've had success with lately -
Finally got around to buying a .040 tungsten. I am mostly welding 20 awg sheet metal and I was very surprised how big of a difference it made. So if you've been lazy like me because its hard to find at your local shop make the effort it was a 15% improvement. I'm still using .040 rod but I may have to try some MIG wire next.
I have also had succes with something else new. Guys on allmetlashaping were debating (for the 20th time) gas vs MIG vs TIG and HAZ and distortion etc. One guy piped in and said he didn't start of stop at all, just moved fast enough that distortion wasn't a problem and showed a door panel he had welded front to back nonstop. Now you know how hard a big open panel like that is to keep from shrinking away. Well I had heard people talk about fusion welding before but mostly thought it worked for the occasional tack welding god or gas welding or whatever, but after seeing his technique I started trying it more and I was like "Holy cow !" virtually no bead and pretty small HAZ and I'm still slow. Now you have to have perfect fitup, any gap at all and the rod has to come in, but I can now pull a 3-4" bead with no filler rod at all. And, in fact, my fusion weld is far superior to my "rod" welding as that still comes out lumpy and inconsistent and most importantly, slow - I am moving almost twice as fast when fusion welding so less heat, less distortion.
It probably only works on steel, haven't tried it on stainless, and I don't think you can strictly fusion weld on aluminum although I have carried the pool pretty damn far without rod before. Since I usually weld both sides of aluminum it works well for the 2nd side though.
Anyway, what works for me is come in hot (my lincon 225 machine is set to about 50 amps). So I come in full pedal and then even before the "spot" turns red I am moving forward (usually pushing the torch) and just keeping that hot red spot from melting through. If I come up to a tiny gap i might just kiss some rod in there. Also, I am moving between tacks about 2" apart so just about the time I am losing it I usually hit a tack and get some fresh pool.
I am far from an accomplished tig welder so if I can do it you can too. The bead comes out so nice and tiny you could almost planish it out (another technique I never believed in before as I always have to grind the crap out of my welds)
Also I was trying ceriated and it was crap, I hadn't tigged in a while so thought I just sucked, but switched back to thoriated and big improvement. So no matter what tungsten is recommended, keep experimenting you may hav ebetter luck with one thing or another.
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