[sschefer]

I almost commented on the frosted thread but I don't think this is related. It is similar symptoms though.

I had a bunch of Home Depot 1/8 x 2" flat stock that I had left over from another project so I cut it up into 6" lengths thinking I would weld a few together and make up a practice sheet.

My goal was to follow all the rules, not skip a thing... Text book if you will. I took a lot of extra time preping it and setting up my torch and machine. IE.. Water cooled 20 torch with a #7 cup, 3/32 2% Thoriated, stickout 3/16", 140 amps on auto balance, 12 cfh of gas. TIG fingers on pinky and bird finger, 3/32 4043 filler rod... Man I was ready!

So here I go, 2% Thoriated, (red tip) spit, spatter, black soot.. I remembered from my book work that black soot was usually a contaminated tungsten. I figured, Jeez I must have dipped it. So I cut a 1/2" off and went at it again... Nope same thing.

I switched to pure with a flat tip just barely rounded which was the same way I prepped the Thoriated and this time it was better but I was using the pedal like a 60's rocker uses a wah wah pedal and the cleaning frost was really wide.

I sat back for a few minutes and thought about what was different from last night when everything worked great and I skipped about half the steps. The only thing I could think of was the aluminum. I grabbed a piece of 5086-H32 and a 5086 rod and it ran a decent bead right of the bat. I grabbed the 4043 rod and the same thing, a decent weld again.

Conclusion, IMHO, the currap they sell at Home depot is junk! However, if you can learn to weld it I think you might teach yourself some really good techniques. I went back to welding on the HD stuff and eventually, without changing the welder settings I was able to find a torch angle and stickout that worked pretty well. Not great but then I'm not a great welder anyway.

So if you've got some of this currap and having trouble with it, practice and practice and practice.. Sooner or later you'll get it and at least in my case, I learned a new level of finess if that's even close to what you can call my welding.

Hope this helps someone. Or maybe it's just my lame ass that's having problems..

[ogorir]

I've welded some of the same 1/8"x1" 6061 strap that you're talking about and didn't have any issues.
pointed 1.5% lanth 3/32 or 2% thoriated tungstens, 135a, full penetration. if you're welding flat, a #6 cup on a gas lens is fine, say 12cfm. I'd also recommend getting a big block of steel if you're just welding strips together. set the big block on or next to the strip you're welding on and use it to run your hand down.

and make sure you clean your stock well. if you didn't clean it with a solvent that was probably your issue. there are a ton of people handling the stock at home depot with greasy hands, ect, plus it's usually in the same cage as the oily mild steel stock. scotch brite and lacquer thinner scrub down works well.

good luck!

[jakeru]

I have used brake parts cleaner (non-chlorinated) for welding prep, and I remember in one case not waiting long enough for it to *completely* evaporate before striking an arc, and I recall the solvent residue (which was likely something such as an alcohol) caused an instant, black sooty mess. So if you are using solvent to clean your parts, make sure its completely evaporated away before you strike your arc! (tip: if you're in a hurry to get welding, Acetone still works, but evaporates *really* quickly.)

I also understand that the aluminum oxide layer is porous, and can trap contaminants you don't want around for TIG welding, such as water and oils. So if you have some aluminum with a "dirty" oxide layer, I would remove the oxide layer along the weld joint before welding it. Buffing off the oxide layer on the surface should ensure a good weld prep. I like using a fine/blue 2" or 3" scotch brite "rolok" style disc on my air powered die grinder for doing that. The discs look like this:

I'll follow up with a good solvent cleaner, and you'll be left (momentarily) with completely oxide-free, "raw" aluminum surfaces.

If I don't feel like breaking out the air tools though and making as big of a mess, (and if I feel the piece may be clean enough) I would probably just abrade the oxides with a hand held stainless steel wire brush, wipe it all with a solvent until the rag comes back clean, wait for workpiece to dry, and have at it.

I have welded before with some 1/16" home depot strip stock ("metalworks" brand I recall?), 1.5" wide. Never did really figure out what alloy that was. But with good prep, it welded just fine using either 5356 or 4043 filler.

[sschefer]

What threw me with this stuff was that I preped textbook. I cleaned the material really well and finished it off with Acetone and a final blow down with dry air.

Thanks for the idea about the hunk of steel to lay my hand on. That's a great idea.

Anyhow, I think I found a couple of problems. I'm not 100% sure but I think some of it's the Radnor Tungstens that I bought at Airgas. I stopped at Matheson and picked up some of their Weldmark tungstens. I sharpened them according to the Miller Handbook and I used a diamond wheel that I picked up at Harbor Freight. As a side note the wheel only lasted for two sharpenings but for 10.00 it was worth a try.

I also had a new Radnor flow meter that I discovered was leaking. I swapped it out for the gauge set that I got with the welder. I'm not sure how accurate the gas flow needs to be but I did notice that after I changed it out I was able to control the weld puddle significantly better.

I picked up another piece of the same material from HD and it welded up pretty well. I warped the heck out of it but that was me not wanting to stop when I should have let it cool down.

I still don't think the HD stuff is anything I would like to build with but in a pinch I think I can now make it work.

Thanks for the comments and advice.. I need all the help I can get.

Steve

[ogorir]

I totally agree about not using home depot stock regularly, but mostly for cost issues. you're paying a 150-250% premium to walk in and buy one 6' or 8' section 'cause you really need it on a sunday afternoon. sometimes the stuff they stock is even alcoa branded.

[sschefer]

I totally agree about not using home depot stock regularly, but mostly for cost issues. you're paying a 150-250% premium to walk in and buy one 6' or 8' section 'cause you really need it on a sunday afternoon. sometimes the stuff they stock is even alcoa branded.

I just checked the piece I have and it is branded Alcoa but also say's "Made in China".

[ogorir]

I haven't had any problems with alcoa-branded aluminum to date, regardless of origin. doesn't mean it won't happen, though. there's not much accountability left in the manufacturing sector.

[sschefer]

Yeah, I agree. Frustration set in at first and I am convinced that the stuff is different but I've got to learn how to deal with it. After all, it aint a perfect world.

I've found a happy medium with the stuff now. 2% thoriated ground at about 30deg with a flat tip and a ground clamp on the workpiece rather than on the table with the workpiece just laying on it. I think the ground did more for it than everything else combined and that makes sense. Different types of AL conduct electricity differently. Keeping the path of least resistance short seems to help a lot. I tacked a tab on it and stuck the clamp on the tab. That was just another experiment to see what it would look like after the tab was removed. Looked fine with a little clean up.

Nice thing about TIG welding, you never stop learing something new. It's even made me a better MIG and Stick welder.