The difference between good shielding gas (pic #2) and not good shielding gas (pic #1) !
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OK, into the weeds we go for those who want to hear what happened and my thoughts about it.
It's NOT going to be short !
Stainless needs a larger shielding area than most everything else, except titanium. Titanium needs the most !
Gas lenses use less shielding gas and have better coverage compared to standard collets, they use screens to restrict and straighten out flow.
Gas lenses allow MUCH longer tungsten stickout lengths
I normally run a gas lense and #8 cup, for just about everything at 20 cfh with pure argon.
They have these new clear pyrex cups now that allow you to see everything instead of the pink or white ceramic that tend to block some of the welders view
So, I ordered some of the newest & coolest larger cups clear stuff from Edge Welding for this stainless exhaust project I've saddled myself with and got started.
Get setup with a #12 cup, 25cfh of argon and start on the old headders, grinding off the old 3 bolt flanges
Had to play with the pulse settings and kept getting tungsten contamination while the weld would have little pockets of fireworks. I thought it was because I didnt prep the welds (pic #3)
My good friend comes over, it's 102 deg F OAT, we play around with some of the equipment in the barn and get ready to tig weld some aluminum, its time for him to try this Dynasty
He tries to light off with my setup, and tells me "something is wrong ...... acts like no shielding gas"
I turn up the argon to 30cfh, same thing, 35 cfh, same thing .............. now we start futzin with the Dynasty settings, as I've not even used AC with it yet.
I've welded everything AC with the Synchrowave up untill today, never had the occasion to try what the Dynasty was really made for - AC
Fast forward, because we're burning ALOT of time futzing around.
He goes home, gets his argon, and a few other things, swap tanks, give it a try ............ same thing. OK, its NOT contaminated argon
He swaps on his cup and swithces from LaZr tungsten (what I run) to pure tungsten, lights up and hes welding like butter. We drop the shielding gas back down to under 20cfh, perfect !!!
Take a little more time playing with the aluminum, then we do the most important part of the day, relax with a cold one or two and shoot our thoughts on what had happened, and life in general.
Now, I've got a mission : I absolutely HAVE to figure out WHY this happened.
He leaves me a couple of pieces of aluminum to play with, first thing I do is put on my #8 pink cup, switch back to LaZr tungsten, works great
Swap cups for the clear #12 and instant crap ...... now I've got an answer.
Do a little research and the clear manufacturers reccommend DC only .......... so I figure the clear just cant do its job on AC, mission complete
EXCEPT
My good friend lays a quiet little comment on me a day or two later ........... he tells me that my stainless welds look cooked and throws a picture at me of a crank he welded with stainless
I see rainbow colors and nice wetted out edges. He quips "proper shielding gas"
Now I'm losin sleep ! He's a good welder indeed, but am I really that bad ?? Why arent my welds rainbow lookin ?? What am I doing wrong ????
He already answered those questions for me ............. "proper shielding gas"
I start looking over everything with a fine tooth comb and I see that my #12 cup doesnt have a diffuser in it. Yup, no screens.
I slap a diffuser in it and get rainbows on my stainless, liquid butter on the aluminum ............ no issues whatsoever !!!
Now I challenge myself, time to weld the female v-band flange half to the UltraFlow stainless muffler. This muffler was stainless mig welded at the factory, as you can see in pic #2, just to the left of the rainbow tig weld
I light off, no prep, and produce the weld you see, rainbow and all.
Any gas gas lense, especially #10 and up NEEDS a diffuser. #8 and down are tapered and can benefit from a diffuser, but you can get away without one. The gas lense has a diffuser in it, but if the cup doesnt taper down to the opening, efforts to slow and straighten out the flow of shielding gas are needed !!
To top it all off, my good friend lays another one on me, says he welds with like 10cfh of argon with a #8 cup on ALUMINUM ..........
Says he's frugal and drops argon down to like 6 or 7 cfh with mild or carbon steel .................
I will be turning down my argon flow AFTER my little stainless project is finished
There .............. story, thoughts, and ramble over.
Hope it helps someone.