What am I doing wrong here.

[Gadget]

I did some practice welding of aluminum tubing today and had some issues with the arc popping and snapping, the metal oxidizing (I think) and couldn't get the puddle to flow. I moved up the pipe with the arc and you can see the results of the popping in the first and fourth photos below. If I moved around the pipe a bit the arc changed back into that nice smooth AC I would consider normal and the weld puddle flowed well (my technique still needs work though).
I tried a new cup thinking the splatter on the cup rim may have been somehow contaminating the weld. I tried argon flow higher and lower, the lower flow seemed to work a bit better. I reground the tungsten too but it had no effect.
I also tried mashing the pedal more to even out the puddle, I noticed that after increasing the heat the puddle started flowing a bit better and when I moved the weld pool ahead it smoothed out nicely for awhile.
Any ideas?
The second and third photos show I did get some reasonable welds after the popping stopped.

[jbman45]

Hi Gadget: Takes practice...but if the settings are right boy it is a lot easier! Hard to tell but my guess is you never really got a good puddle going before you added filler rod. Try some flat stock first before you go to tube and try setting a nice puddle without even thinking about adding any filler.

Also, argon rate should be 5 or 6 lpm or 10/12 cfm depending on your flow meter. If you're using a foot pedal sometimes the dial on the pedal can cause problems since the dial is not linear. If you must use the foot pedal, then set it at 8 or so; not 10 and not 5. I would actually use the switch on the torch to see how it goes first as you learn with no pedal. Try like 40 amps; then 60; then maybe 80 as you try flat stock (1/8 inch or so). Strike the arc at an angle; move torch to 90 degrees and circle a small area to get the AL to turn to a shinny puddle; then move the torch off to the side to about 75 degrees and move fwd a little, then back. If you add filler then add it at about a 20 degree angle and keep it very close to the torch argon blanket. Although there are different ways to add filler I find it best to move the torch a bit left, make nice puddle (they call it a keyhole); move torch back to right a little and add filler as you do that; then move left again to heat up a new puddle. Some get good enough to make it a consistent forward flow but that takes years ofpractice and I don't do that as well.

Settings should be for a start at mid range for frequency and set the W% clean at min or 30%. Tungsten should be small balled or pointed(truncated) is ok; i.e. flat end point.

Good luck and go the extreme and heat to hole thru so you can see what your max limit is as well, then you will know how far not to go.

[junes]

gadget i think it is one of two poblems. It may be that it is anodized aluminum tube you are using and this is how you test for that. Take a multi meter and put it on continuity and touch the tube. If it beeps or shows continuity then its probaly anodized aluminum. If it is anodized aluminum let me know and i will walk you through the process of welding it. If it is not you have a cleaning problem which you do have anyway. Clean the coating on it a little better and dont use sandpaper unless you absolutely have to. If you do clean it off with alcohol or accetone. looks pretty thin walled so use around 100 amps and definately increase the cleaning a bit. Also looks like you have a shaky arc so increase the frequency a bit to tighten up the arc cone. If you didnt clean the metal after welding i would probally rule out a gas problem i really think its a anodized or a cleaning problem. So start with that and post more pictures as you go so we can help. Dont put in 10 to 12 cfm put in 12 to 15CFH. Dont start the arc at an angle unless your not using hf and travel close to perpendicular as you can to the joint. Keep the filler clean inside the gas envolope and keep it at as low of and angle as you can. Dont use a constant forward movement either it wont make as nice of a weld take your time get the puddle flowing float out all the impurities and just relax gadget there no rush and if you dont feel comfortable holding the torch a certain way hold it to make you comfortable if you know what i mean. Just let me know how it goes and sorry for the long post.

[matteh99]

Take a multi meter and put it on continuity and touch the tube. If it beeps or shows continuity then its probaly anodized aluminum.

Junes I think you have the conductivity thing backwards. Straight aluminum will be conductive, anodized won't be conductive. So if you get no continuity the piece is anodized.

Eric

[Gadget]

Thanks guys. I will try the suggestions offered. I did have my pedal set at 5 I will not use the pedal today. Junes, I did not clean the weld after I finished, the photos are showing it exactly as it was after welding.
I was happy to be able to weld the tubing without holes though, I can see the day coming when I can tackle the recumbent tadpole trike project.

[junes]

Yes that's what I meant my bad it was pretty late when I posted that.

[Gadget]

I used a red tungsten, no pedal and just acetone cleaning this time. I didn't bevel and used no filler rod. The weld was the great AC buzz you would expect. The first two photos were with no cleaning after the weld. The dull finish is probably due to my pulling away before the post gas is finished.
I gave it a light brushing in the last photo to clean the dull finish.
Much better this time, thanks for all the help. By the way it wasn't anodized.
Dan

[jbman45]

I'd say old boy you might just have it!! Just a little refining of the technique now and you're on your way! Key is to get the feel of what heat you need and the puddle state so it's nicely wet, congratulations...it's all fun from here out.

For a little fun, use a coke can; don't try to join any but just sit top down with bottom rim up which is a bit thicker. Don't use your pedal, set about half way on the frequency; 60 to 70% on the clean (not a good setting for much else but this keeps head more to the tungsten than the can). NO pulse and try 20 or so amps; then 30 and see how you do. You will be amazed in a bit you can do it! Takes a steady hand once you get going but it's good practice for thin metal. If it's still too hot turn down the frequency and see the difference it makes as well. Good luck...

[LONGEVITY]

Dan,

For aluminum welding, you will need to use grey tungstens. They are both AC DC designed. Red tungstens are for DC welding.

Here is a good article written by our testing team:

TIG Consumables | Longevity Plasma Cutters, Plasma Cutter Accessories, multipurpose units, welders

Thanks

Simon

[bhardy501]

I think you got it worked out. It has to be clean, contaminants will pop up through your weld and make bad spots. I didnt know the part about testing to see if its anodized. Thats nice to know.