Tig welding tips, questions, equipment, applications, instructions, techniques, tig welding machines, troubleshooting tig welding process
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daddytroopa
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    Tue Nov 03, 2020 11:04 pm

Trying to weld a simple aluminum T-joint and its really beating me up. I seem to be getting two puddles, one on each piece of aluminum and I can't make them join. When I crank the pedal and push enough heat to add filler to join the two puddles, I start undercutting the backside and the aluminum "runs". If I don't crank the pedal, then I leave the torch there for so long waiting for the puddle to get big enough to add filler ...then the same undercutting problem

Spec:
1/8" Aluminum, t-joint, super clean and wiped with acetone
2.4mm Lanthanated 2% electrode, sharpened from 30-60 deg angle (tried it all)
3/32 and 1/8" 4043 filler rod (tried both)
#4, 5, 6 cup (tried all of them)

Everlast 200DV
140-160A, pulse off, AC, HF start, 180Hz, 50% bal, 2s pre, 6s post

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cj737
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    Thu Sep 29, 2016 8:59 am

A couple tweaks to make: turn the balance to 65% EP. increase your amps to 180 to get your puddle on the bottom, then wick up and get it on the vertical, and feed the filler favoring the vertical. Having established a puddle on the bottom first, it will be much easier to get it back once the puddle is ready vertically.

You could also be long arcing. Your pictures don’t show the bead wetted in and lots of oxidation. This can be attributed to long arc or balance. Since you’re new at this, let’s suspect long arcing.

I would also tell you to lower the frequency to 60Hz. You’ll get a better puddle on a T joint with it in my experience.
G-ManBart
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    Sat Aug 01, 2020 11:24 am

Have you done any aluminum TIG before trying this? If not you're going to want to take a step back and build off the basics. You need to be able to get a puddle started on a flat piece of aluminum, add filler and run a bead before trying any kind of joint.

1/8" thick aluminum set up like that is doable with 125A as a max, but that irregular cut on your pieces where they meet is going to make things harder to control the amperage since you'll get a keyhole when running a T joint like that...adding filler is what fills in the hole. With the irregular fit you're going to go from a keyhole to blowing through when you get to an area that isn't a close fit.

Also, 50% cleaning is too high...you probably want no more than maybe 30%. I'd back the frequency down to 120Hz (or lower) as well.

Jody has a ton of great videos, but I really like this drill and all the details that are given on how to set your machine...it's worth trying. Watch the video, set your machine up just like they do and you'll be in the ballpark.

https://www.youtube.com/watch?v=YoWSOC_Gx0w
Miller Syncrowave 250DX TIGRunner
Miller Millermatic 350P
Miller Regency 200 W/22A and Spoolmatic 3
Hobart Champion Elite
Everlast PowerTIG 210EXT
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Don't forget that tig t joints aren't simple and aluminium is definitely not simple.
tweake
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daddytroopa wrote:Trying to weld a simple aluminum T-joint and its really beating me up. I seem to be getting two puddles, one on each piece of aluminum and I can't make them join. When I crank the pedal and push enough heat to add filler to join the two puddles, I start undercutting the backside and the aluminum "runs". If I don't crank the pedal, then I leave the torch there for so long waiting for the puddle to get big enough to add filler ...then the same undercutting problem

Spec:
1/8" Aluminum, t-joint, super clean and wiped with acetone
2.4mm Lanthanated 2% electrode, sharpened from 30-60 deg angle (tried it all)
3/32 and 1/8" 4043 filler rod (tried both)
#4, 5, 6 cup (tried all of them)

Everlast 200DV
140-160A, pulse off, AC, HF start, 180Hz, 50% bal, 2s pre, 6s post
the basic cause is your to cold and having to wait which overheat the material.

160a is ok but 50% balance lowers your heat (and pours it into your tungsten). 70% would be better.
180hz takes a bit of heat out as well, lower say 60hz will be better for heat.
2s pre flow is a bit much and 6s post is no where near enough for a 2.4mm tungsten at those amps (especially with 50% balance). bump it up to 10s at least.
a long tungsten taper reduces heat (spreads it sideways). you want a blunt grind, think crayon. blunter it is the more focused it gets.
cup 5,6 is fine.
all of these things add up to quite a bit. its a case of having to get them all right.

finally if you don't get a puddle in a couple of seconds then your set to cold. crank the amps.
tweak it until it breaks
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weldin mike 27 wrote:Don't forget that tig t joints aren't simple and aluminium is definitely not simple.
This!

It's a bit of a 'learned art' to get inside corners to work/weld well on alu.

But here Jody's mantra really helps.. "Keep a tight arc!"

Alu corner joints go much better if you:
  • Make sure the fitup is spot-on without gaps
  • Get the base metal brushed with a stainless brush to reduce the oxide coating as much as possible
  • Clean, clean, clean, then clean again (base metal, filler rod)
  • Get the tip of the tungsten 'buried' into the corner when lighting up
  • Tip of the tungsten not ground at too shallow an angle
  • Make sure your ground is good
This will allow you to light up deep inside the corner, so the (inevitable) arc wander will only want to 'jump' right into the root sections. By quicky pushing a lot of amps you can get both sides to puddle and usually a small dab of filler then gets you a nice tack.

Do this along the way in a few places.

Now, again keeping it tight, light up on the tack and the puddle is now already linking both sides, move forward and keep the arc into the corner so any dabs flow fully down into the root.

Then practice, practice, practice.. And expect to dip the tungsten a lot as you need to develop the muscle memory to ever so slightly raise the torch on each dip as the puddle will 'bulge' a little before settling down.

And once you do get it going decent and get the hang of it, expect it to suck again if you go back in a few months and do another inside corner weld :lol: (really something that needs practice and constant use to stay good at it..)

But once you do get this dialed in and more 'automatic' then things with a less optimal fitup will get easier to manage.

Bye, Arno.
BillE.Dee
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hello daddy T...ya want the hertz about 90, max--the balance around 30 (the everlast machines are backwards from others) ,, get the boogers off of the edges of the material and brush with a dedicated stainless brush. Practice on a flat piece of material by just running beads without filler to get used to the machine. Keep the tungsten CLOSE to the material and tilt just enough to see the tip from under the cup (#6), gas flow around 12-15 cfm, preflow low, post flow 4-6 secs. I think ya got enough amps to get you started on flat practice piece. Don't start right on the very edge,,steady application of the pedal to get the puddle going. Forward, back a touch, forward, back a touch. 'the aluminum will take on heat.
What i've stated above is what works for ME, everyone is different and has find what works for THEM . take all of this information provided and put it together.
Clean, Clean, Clean, , , Practice, Practice, Practice.
BugHunter
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Unless I didn't see it, you never mentioned using a new, clean SS wire brush and breaking up the oxide layer before you began. Clean aluminum is important, but might not be quite as important as wire brushing the area to be welded. That really helps to clean it, and if the material is older (has a lot deeper oxide layer), you'll have a hard time getting the surface to wet out with all that crud on the parts.

It also doesn't look like you filed the edges of the parts first. Get all those burrs off there so you don't have little points trying to make the arc wander around. Everything else I see was covered above by other folks.
sbaker56
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I've tigged aluminum so oily it was smoking when I finished :lol:, wasn't even wiped down let alone wire brushed. Cleaning is important, but at least on aluminum not usually the reason things end up like this.

A couple thoughts I had, at 50% balance and 140-160 amps you're cooking that tungsten a lot more than I'd like, As someone else said you want at least 60-65%EN even on the most filthy aluminum, and at 50/50 balance or even less than 70% I'd prefer a 1/8 tungsten at those amps, as I tend to notice a bit of arc instability and spitting with 3/32 with those parameters.

More importantly though it sounds like arc length is your problem, aluminum is a terrific conductor of heat, and you're clearly cooking the hell out of the metal, nearly half of the entire plate is melted on the backside which tells me you're concentrating the heat just about as well as a rosebud torch, Try getting a nice ground piece of tungsten and really holding a tight arc when you light up.
cj737
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sbaker56 wrote:I've tigged aluminum so oily it was smoking when I finished :lol:, wasn't even wiped down let alone wire brushed. Cleaning is important, but at least on aluminum not usually the reason things end up like this.
Dead right.
tweake
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BugHunter wrote: It also doesn't look like you filed the edges of the parts first. Get all those burrs off there so you don't have little points trying to make the arc wander around.
good point.
tho its not just arc wander. i've had those little burrs vaporise, blow up. unfortunately that aluminium ends up coating your tungsten. i deburr and round the edges a tad. seen plenty of sharp edged corners disappear in a flash.
also remember to clean all the aluminium swarf off the work and table. seen it so many times where a bit of swarf will get sucked into the torch and splatter the tungsten (anyone know the physics of why that happens?).
tweak it until it breaks
tweake
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BillE.Dee wrote: What i've stated above is what works for ME, everyone is different and has find what works for THEM . take all of this information provided and put it together.
Clean, Clean, Clean, , , Practice, Practice, Practice.
+1
everyone is different. the important bit is to understand why things are done, then you can adjust it to your situation.
tweak it until it breaks
BugHunter
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tweake wrote:good point.
tho its not just arc wander. i've had those little burrs vaporise, blow up. unfortunately that aluminium ends up coating your tungsten. i deburr and round the edges a tad. seen plenty of sharp edged corners disappear in a flash.
also remember to clean all the aluminium swarf off the work and table. seen it so many times where a bit of swarf will get sucked into the torch and splatter the tungsten (anyone know the physics of why that happens?).
During the EP phase of the AC waveform energy is being sent from the part to the tungsten. That energy is what lifts up the oxide layer and pulls it off the surface of the aluminum. I would imagine that's why it vacuums up anything that's loose and coats the tungsten. (Edit to fix vtt)
Last edited by BugHunter on Thu Nov 05, 2020 10:59 pm, edited 1 time in total.
sbaker56
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BugHunter wrote:
tweake wrote:good point.
tho its not just arc wander. i've had those little burrs vaporise, blow up. unfortunately that aluminium ends up coating your tungsten. i deburr and round the edges a tad. seen plenty of sharp edged corners disappear in a flash.
also remember to clean all the aluminium swarf off the work and table. seen it so many times where a bit of swarf will get sucked into the torch and splatter the tungsten (anyone know the physics of why that happens?).
During the EP phase of the AC waveform energy is being sent from the part to the tungsten. That energy is what lifts up the oxide layer and pulls it off the surface of the aluminum. I would imagine that's why it vacuums up anything that's loose and Coach the toston.
Huh, funny I've actually never really thought about it before, but it does seem like I can keep a pristine tungsten on steel for quite a while but on aluminum it's an inevitability that even when I'm sure I haven't been dipping it the tungsten ends up coated with a thin layer of aluminum, I wonder if that's why
Jakedaawg
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By the lack of a clear etching line from what I can see on the little phone pictures I look at it would appear that you are not holding the tip close enough. You have to get it right down in there. So close that when you dip the filler in you have to lift the tungsten a little to keep from getting it wet. Maybe too much of an angle as well on some of those cooked blobs. The angle being too much side to side wise pulls air in from behind.

The puddle will form on one side and then you kind of pull it up to the other side.

When I run 50 on the balance I ball my tungsten. Seems to work better for me. I only weld dirty aluminum so I do run 50-60 (40-50 on your machine) quite a bit. I am in the marine service business so all the Al has been in the water for years soaking up minerals or worse, minerals on one side and oil on the other side.

Give it time, soon you will be able to do it laying on your back while watching in a mirror and working the pedal with a knee
Miller Dynasty 280 DX, Lincoln 210 MP, More tools than I have boxes for and a really messy shop.
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