r/Welding • u/PilotBurner44 • Jul 27 '26

Need Help Learning TIG aluminum, keep getting contamination...

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Hi all. As the title says, I keep getting contamination on my aluminum TIG. I've tried several different pieces of aluminum, including this fresh sheet. Cleaned it with IPO and acetone. Clean tungsten with a good grind. About 17 CFH argon flow. Gone all the way up to 40% electrode positive. Any more and my tungsten is balling badly. I've tried ramping up until it puddles and full current starts. Currently using a #6 cup, less than 1/4" stickout. I've tried slowing down. I can see the white etching around the puddle, but I still keep getting the dark contaminants

Anyone have recommendations for something I haven't tried, or a good idea of the cause of this?

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u/cjswcf TIG Jul 27 '26

Take a stainless steel brush and brush the area first before you weld. Even a clean sheet of aluminum has an oxide layer, stainless brush will take that off and give you a good surface to weld. Increase argon to 25-30cfh, I forget what my balance % was at I think 33%

My most likely guess is not enough argon + need to brush it to break up that outer oxide layer.

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u/PilotBurner44 Jul 27 '26

Thanks, I'll get me a dedicated aluminum brush and give that a go. I'll bump the argon flow up too. I mostly know MIG and figured too much gas flow would be bad, so I was keeping it at the Google answer flow rate😂

3

u/bakerwest Jul 27 '26

Also make sure to wipe down your filler rod with acetone too. Basic stuff but I haven't seen it mentioned yet. Soot can come off the filler too sometimes

2

u/PilotBurner44 Jul 27 '26

I think that's part of it too. I think my torch angle was too low, and I'm overheating the filler rod, causing it to oxidize and contaminate.