Large Diameter Gas Lens Kit
Why would you want a Large Diameter Gas Lens kit for Aluminum?
Dirty Aluminum and Aluminum Castings need a lot of cleaning action from the AC arc in order to weld clean and avoid porosity.
Since the AC arc cleaning action seems to only want to go where there is argon coverage, then it makes sense that a larger cup with a gas lens would help provide maximum cleaning.
So I decided to use a Large Diameter Gas Lens kit set up with a #8 cup along with a 1/8" 2% lanthanated tungsten.
I set the AC balance lower than I would normally to around 60-63% EN (37-40% cleaning EP)
And I let the cleaning action work for me before puddling.
You can see in the video some brown stuff cooking out when I danced the arc cleaning action over the aluminum.
I used 4047 filler wire because 4047 really helps to reduce porosity in aluminum castings and also on dirty aluminum.
After a low preheat of around 150f, I welded all the corner edges first to build up some heat into the part.
Then I set in to stacking beads on the heavy areas.
I used the stock Esab Tig torch that came the Rebel 205 and to be honest, I didn't love it.
The cable was stiff as a brick and after just a few beads, I could feel my wrist fighting to stay steady.
It made me appreciate the super flex torch cables I have on other machines.
Another plus for using a Large Diameter Gas Lens kit is The extra mass from the large diameter gas lens helped a bit in keeping the torch from overheating ...but it got pretty darn hot anyway.
A 150 amp torch can only handle 200 amps for brief periods.
I recently got a 200 amp air cooled tig torch that I plan on hooking up so stay tuned for that blog post and video.