impossible aluminum setup?

by liquidluv4d

I have a 1" to 2" aluminum weld joint with a 1/4" x 45' bevel. Final weld will fill the bevel and 1/4" fillet on top. Running a Miller 350 Syncrowave. now the fun part.... All we have in the shop is Argon for the gas, all we have is pure 1/8" tungsten and 1/8" 2% thoriated tungsten, and all I have for filler metal is 1/8" 4043 aluminum TIG rod. My boss is trying to tell me that this joint can be welded under 180 amps??????

Right now I'm preheating the thick aluminum to around 500' F and can't get over 250 Amps without my tungsten wanting to dance right into the weld. And I still can't get fusion down into the weld joint. My biggest concern is that the weldment gets stressed tested at over 9 tons. My other concern is that there is actually an approved weld procedure that says you can weld 1" aluminum to 2" aluminum under 180 Amps. I've tried all cup sizes, the above mentioned tungsten sizes (also 5/32" pure but it just turns black and nasty), and this job has to be sent to anodizing, stress testing, and final machining by Friday! LOL

Any answers or advice would be very much appreciated. I'm honestly open to anything at all because I'm about to just tell them I cannot do this job with this equipment. I'd like to try Helium, or different tungsten, or a larger machine.

--------------------------------------------------

My apologies for being a day late and a dollar short with this reply...but I dont really have a simple answer anyway. I dont see any way of doing that job without helium.

I tested some 180 amp tig welders a while back with pure argon and could barely puddle the metal.

I added helium and could run a decent bead at 180 amps on a piece of 1" thick aluminum with no preheat.

Also, the higher the preheat, the more the temper changes and tensile strength goes down in the heat affected zone.

again, sorry for the late reply, but I have been extremely busy.

Another last tip is to adjust the ac balance as high as possible ...that will help on the electrode dancing from all the heat.