First aluminum run in 14 years... some advice please...

Neighbor gave me some aluminum, it's whatever alloy you get from Home Depot most likely, 1x1/4 bar stock. Hit it with a roloc till it was clean and shiny, started with a 3/32 with a point (been a long day, didn't think about it) sharpened to 2.5x diameter. 3/8" projection on a 6 cup, 3/32 4043 filler.

Set it to AC, abt 9lpm Ar, 150 amps, but I was playing the pedal so I don't know exactly how much. Set the balance and frequency both straight up on my 200DX.

http://lh5.googleusercontent.com/-lS...DCD30BE638.JPG

Width was a factor of arc length, had a bit of issue early on, broke my hand last weekend so it took a bit to get to where I could control the torch.

Ran a few more

http://lh5.googleusercontent.com/-gi...68FA1FFF93.JPG

Played around a bit with balance and frequency

https://lh6.googleusercontent.com/-D...CAC46A6B0F.JPG

The whole time, it was spitting and popping, not a nice smooth sound. Had a few times where it was just did not seem to want to put out an arc cleanly and a few times it felt like the machine cut out. I had the bar on the steel table, clamp had the curve on the bar, double flats on the table, so I doubt it was a ground issue.

Here's one spot, not sure what the hell happened, tried adjusting the balance from about 10 o'clock to about 2 o'clock, no bueno...

Thought I had it ready to add and then... turd

http://lh6.googleusercontent.com/-R_...B2C4ADC16E.JPG

And just below that one, I went back to both dials straight up, put on my TIG Finger and ran a nice pretty one.

So, what about the popping and stuttering, any thoughts on the half-second drop-outs, felt like it just shut off momentarily, like a brownout or broken ground, but the ground was to the piece itself and the table the metal was sitting on...

Set the balance to 30% and the frequency to 120 Hz and try that.

Balance is a bit off for sure. Set the left yellow knob at 2 o'clock (about 120Hz) and the right knob at about 10 o'clock (about 30%). As Ram mentioned. Tweak the right for etching and the left for width.

Quote:

---

Originally Posted by everlastsupport

Balance is a bit off for sure. Set the left yellow knob at 2 o'clock (about 120Hz) and the right knob at about 10 o'clock (about 30%). As Ram mentioned. Tweak the right for etching and the left for width.

---

Actually, Mike on this one it is fully left for 30% (DX). Also cut the gas flow down to 7 and decrease cup size to a 5 or 6. What type of tungsten did you use?

Put a little bit of a flat on your tungsten so it doesn't melt away so quickly. Set the machine to max amps (200). Put the balance all the way counterclockwise, then give it a little tiny tweak off the stop just a little).

When you start the weld, floor the pedal to get teh puddle quickly. then, as you move, you may need to taper off a little. The 1/4" thick bar will take a good bit of heat to get a good puddle. You are pretty much just putting a bead on top of the plate with very little wetting at teh start. Look at your beads as they progress and you will notice they get a bit wider and seem to flow out better. This is because the heat is built up in the material.

Hit it harder from the start and it will wet out much more quickly, then keep an eye on it and taper off as needed to control the heat and width of the bead.

Rule of thumb is about 1 amp per thousandth (.001") material thickness. This is a little different because it is only 1" wide, (and you don't have 250 amps anyway)

I think you might find it a bit easier to start with something in the ~ .125" thick range, at about 125 amps. See if you can find something that is wider as well so the heating is more even and gradual.

You also want to be sure your distance you keep your tungsten from the workpiece is consistent and tight.

You have clean materials and good inert gas shielding setup. Intermittent arc probably caused by unreliable ground (or bad connection somewhere in the high-current welding circuit).

The area with black "soot" looking powder on the surface is likely tiny particles of aluminum oxide from the hot tungsten touching aluminum.

I agree with others regarding decreasing AC balance to 30% to narrow the cathodic etch width (taking heat off your tungsten, and putting it more into your workpiece), and aiming for more consistent weld bead width.

Also, practice tapering off your current at the end of the weld bead (and adding an extra dab of filler as needed while doing it) to prevent the crater from forming.

What do you guys think about cleaning with the roloc or scotch brite discs??? Would they contaminate the metal??? I thought you needed to stick with a stainless wire brush and keep it clean for alum only??? Just tossing an idea out.

Brian you are right...especially if they are overheated.

Thanks for all the advice folks. Spent the day going back and forth between my lathe and the welder. Started the day with the aluminum again. Dropped the balance to 30 (all the way anti-clockwise on my machine) and had the freq on 120-125, a bit hard to tell. Didn't see the advice on flow, so it was still around 9ish LPM (is it the top, middle or bottom of the ball you read from?)

Brushed the hell out of the bar with a SS brush (I have one for each metal) and with the combination of that and the knobs, popping and dropping went away.

Still used the 3/32 1.5% lanthanated, still with the point, it's holding up great, I get about a 1/16 ball on the end, nice clean focused arc.

Regarding hot or cold, you can't see from the pics, but those are truly hot enough and penetrate deeply. Most sit barely 1/16 proud of the surface, great puddle, stuffing a 3/32 4043 into the edge of the puddle brought it up a little taller. Next setup will be some joints so I can really gauge penetration.

Quote:

---

Originally Posted by Brian Ski

What do you guys think about cleaning with the roloc or scotch brite discs??? Would they contaminate the metal??? I thought you needed to stick with a stainless wire brush and keep it clean for alum only??? Just tossing an idea out.

---

Scotch brite on aluminum does actually a very good job of removing all the surface oxidation. The scotch brite conforms to irregular surfaces so can effectively clean complicated shapes too. You can do it by hand (with a hand pad) or with a power tool (like an air die grinder with a roloc disc.) I agree with what Mark said about not letting it overheat, which is only a potential concern if using power. When the disc gets loaded up, it's a good idea to clean it also (or replace). General rule of thumb when using any power tool for prepping aluminum for welding, is try to keep the aluminum cool enough to touch or hold; never let it get hot enough so that the surface "smears" (and you'll see if gets kind of a mottled texture when this happens, and glops of aluminum will be stuck on your tool). This holds true for using sandpaper as well (like a flap wheel).

I also expect the scotch brite will leave behind dirt that needs to be wiped off with a solvent rag after, before welding. (Which Trip said he did). You can check the rag to see if it's getting dirty (in which case, it's helping). Some "fresh" clean aluminum stored in clean conditions (like indoors away from wet) can sometimes be welded with no prep at all, although a little bit doesn't hurt, if there is any oils on it it will at least benefit from a solvent wipe. Hope this helps.