Need help with tig on Al

[Hobbyist]

I'm having trouble welding aluminum with my dynasty 200dx. It seems like the whole thing just wants to melt into a lump. I've got some 1" square tube I'm playing with. The wall is about 1/16". Probably 6061 but I'm not positive. Filler is 1/16" 4043. I've tried butt joints but mainly just running a bead on the side of the tube. I'm using 3/32 lanthanated, pointed. Welder set at 125A, balance 65, freq 125.

It seems like I can't keep the puddle any smaller than 1/4-3/8". Any less heat and it freezes instantly when I try to move or add filler. But I add just a little more heat and I've got this jumbo puddle. At first I couldn't get the filler near it without the end of the filler melting into a big blob before reaching the puddle. I must be getting better because now about half the time I can actually add some filler to the puddle.

With this jumbo puddle, I end up with a wide, flat bead. Usually the "stacked coins" look is there, but looking like it's almost been melted into a smooth surface.

It also seems like I'm using a much shorter arc length than on steel. I say this because it seems like the tungsten is always getting fouled, while I've almost stopped doing that on steel. I think maybe it's that I'm trying to turn down the heat so the whole thing doesn't melt, but then moving closer so something melts.

Also, the finished weld is frequently dull white rather than shiny, kinda like the metal on either side.

Anything I should be doing differently, or do I just need to keep practicing?

[HAWK]

Hobbyist,

Too much heat! Dial down around 60 amps as a starting point and move up from there. USE A 1/16" FILLER ROD. Your material is melting before the filler. Go to a 1/16" tungsten and it will be easier to control. Start the balance at 70 or 75. The arc frequency of 125 is fine unless you are using something other than 100% argon.

Start your puddle by initiating the arc with your foot pedal and swirling the torch in a counterclockwise motion over the starting area. It should puddle in a few seconds. It may take a little longer than steel. If it won't puddle, then turn up the amps by 10 and go again. If it gets too soupy too quick, back off the pedal and/or turn down the amps. Once you have a puddle add filler and advance the torch, add filler, advance, etc.

If you dip your tungsten in the weld pool or filler rod, regrind it before welding. If not things will just get worse fast! Grind it to a point and then put a small flat on the end for use with the Dynasty.

The dull finish can be a number of things: The wrong filler-try 5356 or even 1100. Too little or too much gas-12-20CFH is a good range. I use 17CFH unless it is an odd joint. 12CFH should be good unless it is a drafty shop. Also clean your material with Scotch Brite pads and wipe with acetone before welding. Clean your filler rods the same way before welding.

[HAWK]

Hobbyist,

Once you get a bead running we will address the issue of bead color and balance more in depth. Right now concentrate on running a decent bead. This should come pretty quickly. Perhaps an hours worth of practice with these hints will have you up running. The main thing you need to know about the balance setting is if bead becomes "prickly" like miniature briars, then the balance is too high. If the whitish area around the bead is more than 3/32"-1/8" wide, then your balance is too low. That is a general statement and can change under specific circumstances.

[Hobbyist]

Hawk,

Thanks for the comments. I was using 1/16 filler already, but I'll try switching to 1/16 tungsten too. And I'll try turning down the heat. At least I wasn't doing everything wrong. I'll try to get some pics posted too.

A question about flattening the tungsten: how big should the flat be, for 3/32 and 1/16?

[HAWK]

Hobbyist,

Once tapered to a point the point should have a land (flat spot) of .030" on the 3/32" tungsten and .020" for the 1/16" diameter tungsten. These are approximations and not that critcal for manual hand welding. The larger the flat the less taper length you will have.

For this application I'd use a 1/16" lanthanated tungsten alloy with a 20 degree taper and .020" or less flat. The big thing is not use too much amperage and let the torch circle until you get a puddle. Once you start the puddle and begin welding the work piece will heat up throughout due to the high thermal conductivity of aluminum.

I don't like preaching, but this is as important as anyting when working with aluminum. Clean it thoroughly! The metal will melt before its oxidized coating causing the lumpy meltdown you have described.

Let us know how it turns out.

[Engloid]

Going to 1/16" tungsten isn't going to do much other than cost you more money. I've welded materials as thin as .004" with 3/32" tungsten...without problems.

I may be missing something here, but typically you only sharpen the tungsten to weld with DC current, not AC.

[HAWK]

Engloid,

I too weld most everything from 5-300 amps with a 3/32" lanthanated tungsten alloy on a Dynasty 300 DX. I suggested the 1/16" tungsten as it is usually easier to control the arc for a beginner. Yes, he can weld with 3/32". I am just trying to think of possible variables to eliminate to help make things easier.


I ball tungsten for AC on sinewave and squarewave machines. I sharpen to a point and put a small flat on the end when welding AC or DC with advanced squarewave machines like the Dynasty. Hobbyist is using a Dynasty 200.

[JOHN1]

Give him a break!!

Engloid:

I am a beginner also.

Don't slam Hawk for his input.

Geez, can't even make a suggestion to help here without someone being negative. Do it some where else Dude or say it differently!

John

[GaryM]

Well put John!

I dont care about trying new things with tig welding so $15 for some different tungsten is a small amout when compared to the gas for practicing.

Gary

[AV8OR]

Dear Engloid,

Em Miller boys like to sharpen them on the inverter machines for AC welding. Click Here for more intel.

[HAWK]

Engloid,

I am confused. I read somewhere you use a Dynasty 300DX daily at work. How do you prep you tungsten for AC when welding aluminum or magnesium with this machine? If there's a better way I'm all ears. By the way, I think mentioned before, nice Cu-Ni welds!

[Engloid]

You guys act like I slapped his mom or something.

I did use the dynasty 300 at work, but I changed jobs.

I usually would just use a blunt tip for AC work. I like the advanced features of the new machines, but really never found much necessity for using these features on the job. However, it's great for fillet welds...but then so is DC with helium gas.

Unless I missed something, he never mentioned adjusting to using a sharp tungsten. His mentioning that the puddle goes from nothing to a large puddle indicates that he isn't really utilizing these advanced features well enough to work well with sharp tungsten.

I believe this is the problem. Maybe some of you that have done more of this can give him some tips in this direction.

[ASKANDY]

All our Dynasty units are designed around a pointed tungsten. Although you may use a blunt one, it usually doesn't start as good. Because of the wave shape and time soent at electrode negative, heat is kept to a minimum on the tungsten and prevents balling. Unless you adjust the balance control down into the 60s, it should stay well pointed.
I'd jump the balance up a tad to around 70-75 like Hawk said and run your amps around 85. This will give you a better resolution on the foot pedal and not be so touchy when adjusting the amps. With the main amps set higher, your pedal resolution is narrower giving you a lot more amps for slight movements of the pedal.
Clean, clean, clean and it would help to know what type aluminum you have cause it will make a big difference.

Good luck and have fun!

A-

[HAWK]

Originally posted by Engloid
You guys act like I slapped his mom or something.

I did use the dynasty 300 at work, but I changed jobs.

I usually would just use a blunt tip for AC work. I like the advanced features of the new machines, but really never found much necessity for using these features on the job. However, it's great for fillet welds...but then so is DC with helium gas.

Unless I missed something, he never mentioned adjusting to using a sharp tungsten. His mentioning that the puddle goes from nothing to a large puddle indicates that he isn't really utilizing these advanced features well enough to work well with sharp tungsten.

I believe this is the problem. Maybe some of you that have done more of this can give him some tips in this direction.

Engloid,

I do not view your comments as offensive. We just have some different thoughts on the subject of tungsten prep. Thanks for joining this forum. You really do some nice free hand work.

[GaryM]

Ya very nice welding Engloid! I wish you lived close to me for a few lessons

Gary