Here is some good tig welding info - Add a little Helium and BAAM!! Its like having more amperage.
Did you know that using a 50/50 mix of argon and helium will make any aluminum weld better?
Especially the thick stuff.
Ever light up on a really thick chunk of aluminum like a transmission case and have to wait like 10 seconds for the metal to puddle? Add helium to the mix and no waiting...
Really..., Its like adding another 20% of amperage.
That really helps when you just barely have enough amperage from a small tig welding machine.
I have a miller dynasty 200dx and for really thick aluminum castings, It just does not have enough balls. But When I add helium along with a preheat on the stove when the wife is looking the other way, suddenly , I can get the job done
...and another benefit is that it actually welds cleaner too.
More Down and Dirty Tig Welding Info
And another tip...Did you know that you can do certain aluminum welding jobs with DCEN and straight UHP helium for shielding gas?
UHP stands for "ultra high purity". and thats what you need. Not the stuff they fill balloons with.
I remember one job that this worked great on was an aluminum injection mold.
The pitting that sometimes happens when the A/C does its thing was just not tolerable. All the mold needed was a small fill of a chipped area.
So I Hooked up some UHP helium, increased the flow rate to about double what I would have used with argon, lit up , puddled, added a few drops of filler rod...and done. No pitting, and the mold barely got hot. which was nice because there was a bunch of sealant around the edge that would have needed to be replaced.
Helium for Tig Welding Steel
But there is another use for helium, helium mix that is... if you have a small inverter welder that only puts out 100 amps or so and you have some pretty thick steel to weld. Using a helium mix makes it penetrate a lot better. Sometimes even too much if you are not careful.