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Lincoln T-355 1/4" alum tungsten balling

Posted: Tue Aug 17, 2021 2:51 pm
by alex.paap
Hello Everyone,

I'm pretty new to welding and having major issues with my tungsten balling up to at least double the electrode diameter and I can watch the molten ball of tungsten jiggle around as I'm welding. Material is 2x2x1/4 6061 aluminum square tubing. I've had a lot of success welding thinner 6061 on my little everlast with a 3/32" 2% lanthanated and I can't seem to get the same results on the bigger machine with thicker material.

A couple of times, I've gotten into a groove and produced ok looking beads and then had horrific results immediately after with no settings changed. I'm pretty sure its because my tungsten degrades and the arc starts wandering wherever it wants to. It's also leading to my filler sometimes curling up and melting before I can dab the puddle.

My settings:

Lincoln square wave T-355
Amps: 190-220 AC
Gas: 100% Argon @20CFH
Cup: #6

Material prep: 1/8" bevel and hit with a sanding disc, stainless brush and then acetone wipe

Tungsten: Either 3/32" 2% thoriated or 1/8" pure. Both behave similarly although the pure seems to last a little longer (I'm guessing just because it's larger)
Tungsten Prep: Normally I taper about 1.5x the diameter of the tungsten to a point and let whatever happens happen. That wasn't going well so I've tried blunting the tip (no different) and switching to DCEP and putting a ball about the diameter of the tungsten on (best results so far but still turns into a gigantic blob far quicker than I would like)

Balance: I've tried all the settings and haven't seen any noticeable difference. Tried 1 (more EP) and 9 (more EN) and tungsten balled just as quickly in each setting but 9 does seem to get a puddle going faster. Even in auto-balance mode, I get an enormous wiggly blob of tungsten after a few seconds of welding. I almost feel like there's a problem with this part of the machine.

High freq: continuous

post flow: 10s

The attached pictures are some of the first beads I ever ran on aluminum with my everlast (not great, but they look like welds, and I don't crater the ends anymore lol), I'll post some of my T-355 welds when I go in tonight and a pic of the machine settings. I have all the bells and whistles turned off.

Any ideas on how I can fix this?
-I have some 3/32 2% lanthanated that I want to try but I'm not super hopeful about it.
-Noticed in the manual theres a knob to control Hz. If this is too low could that be screwing me? I'm not an expert but the buzz sounds similar to what I'm used to.

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Re: Lincoln T-355 1/4" alum tungsten balling

Posted: Tue Aug 17, 2021 4:45 pm
by G-ManBart
Lots of things going on here. For one, thoriated tungstens don't work well on AC at all...don't even bother. Lanthanated will be much, much better. Pure will work, but you have to ball it when you start and expect to redo it periodically. You should start out using something like 30% EP on the balance. Much more than that and you're going to put a lot of heat into the tungsten.

Are you 100% certain the torch is connected to the negative output? I think Lincoln calls that "To electrode" or similar.

Your gas flow is pretty high for a #6 cup....I'd lower it to 15 CFH or something along those lines. Too high a flow can cause turbulence and poor shielding and possibly not cool the tungsten properly.

I didn't think that machine had adjustable frequency, but pulse was optional...is that the knob you're talking about?

Re: Lincoln T-355 1/4" alum tungsten balling

Posted: Tue Aug 17, 2021 5:06 pm
by BillE.Dee
What BArt said but also, you stated that you were driving an everlast prior to the lincoln. I'm not for certain but does the balance adjustment adjust the opposite of the everlast? Try turning the balance knob closer to the 3 O'clock position.

Re: Lincoln T-355 1/4" alum tungsten balling

Posted: Tue Aug 17, 2021 7:44 pm
by Toggatug
I'd be double checking my connections are correct and tight. Had the same kind of problem when my miller was shipped to me for a demo. They had the ground and torch leads backwards and I was so excited to try the new machine I didn't even think to look things over closely.

Did the same as what you describe when the machine was telling me I had low cleaning. Turns out I was past the balling point of the EP/EN scale and at the catastrophic tungsten explosion at the amps I was trying.


Also not sure if you can but I'd bump up the amps if there available. On 1/4" ally I normally set my machine at 275+ so I can get a puddle nice and quick, you might find it helps

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Re: Lincoln T-355 1/4" alum tungsten balling

Posted: Wed Aug 18, 2021 12:05 am
by tweake
alex.paap wrote: Tue Aug 17, 2021 2:51 pm
Amps: 190-220 AC

Tungsten: Either 3/32" 2% thoriated or 1/8" pure. Both behave similarly although the pure seems to last a little longer (I'm guessing just because it's larger)

-I have some 3/32 2% lanthanated that I want to try but I'm not super hopeful about it.
3/32 is to small for that sort of amps and your amps is way low for 1/4 aluminum.
thoriated or pure won't work well.
something like 1/8 2% lanthanated would work well.

Re: Lincoln T-355 1/4" alum tungsten balling

Posted: Wed Aug 18, 2021 4:56 pm
by alex.paap
Thanks everyone for the feedback!

3/32" lanth did the trick for me!!!

Balled it on EP and left the balance almost on full penetration (8-9).
Bumped up to a number 8 still at 20 CFM.

Ran the amps at around 220-245.
Millers weld calculator suggests 190-220A and a 3/32" but I found higher to be working better.
all of these joints are beveled so starting isn't too difficult but I'll try going higher. I didn't wanna deviate too far from miller's recommendations. I'm an engineer during the day and get caught up in trusting manufacturers specs haha

I already told the owner to get me 1/8" blue tungstens and a gas lense. Resources are scarce at his shop- (red and green tungstens only, like 2 cups, and yeah... Made for a good learning experience tho)

Pics using 1/8th 4043 filler:

Any additional comments, questions, or concerns are appreciated.

Oh and the frequency knob only changes the high frequency, not the actual welding Hz if anyone is still interested.

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Re: Lincoln T-355 1/4" alum tungsten balling

Posted: Wed Aug 18, 2021 4:57 pm
by alex.paap
Attached images. Wasn't sure if they were working

Re: Lincoln T-355 1/4" alum tungsten balling

Posted: Wed Aug 18, 2021 5:36 pm
by Toggatug
I find with all the weld calculators they often recommend rather low once you go north of 1/8 or 3/16"

Also I set higher because I want a puddle formed to full size within 3 seconds or less. I can always back off as needed but can't go further than full pedal obviously.

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Re: Lincoln T-355 1/4" alum tungsten balling

Posted: Wed Aug 18, 2021 6:10 pm
by alex.paap
Yeah that's a good point.

What would you recommend for the inside corners? I did a couple practice ones at 240A and had to camp out for forever to get started. Then by the end of the weld I was down to what felt like 1/2 pedal. Super wack.

I'm looking forward to trying out some 1/8 tungstens and really ramping it.

Re: Lincoln T-355 1/4" alum tungsten balling

Posted: Wed Aug 18, 2021 6:17 pm
by Toggatug
That's the joy of ally. Takes a lot to get the spot your trying to weld hot since the material pulls so much of your heat away from the weld joint.

Part of the reason for the big overage in amps

And mm I don't do many inside corners mainly I do butt welds or laps with the work I do.

If I had to hazard a guess I'd set my machine at 300-325 on a inside corner 1/4" ally.

Just remember the higher you set it the less control your pedal will give you, otherwise I'd just leave my machine at @ 400 and weld whatever gets out on the bench, but I wouldn't have the control needed for thinner materials like 24g steel (not fun at all to weld by the way)

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Re: Lincoln T-355 1/4" alum tungsten balling

Posted: Thu Aug 19, 2021 12:30 am
by tweake
alex.paap wrote: Wed Aug 18, 2021 4:56 pm Thanks everyone for the feedback!

3/32" lanth did the trick for me!!!

Balled it on EP and left the balance almost on full penetration (8-9).
Bumped up to a number 8 still at 20 CFM.

Ran the amps at around 220-245.
Millers weld calculator suggests 190-220A and a 3/32" but I found higher to be working better.
all of these joints are beveled so starting isn't too difficult but I'll try going higher. I didn't wanna deviate too far from miller's recommendations. I'm an engineer during the day and get caught up in trusting manufacturers specs haha

I already told the owner to get me 1/8" blue tungstens and a gas lense. Resources are scarce at his shop- (red and green tungstens only, like 2 cups, and yeah... Made for a good learning experience tho)
i havn't checked recently but the miller online calc is (or at least was) incorrect.
i have the paper version here and for 1/4" aluminium it recommends between 260 and 340 depending on joint configuration.

as far as cups go, smaller is better. as long as there is a little bit of frost line outside of the weld then its fine.
with the smaller cups you tend to get a bit more heat. i would use a 6 or 7.
gas lens not required unless you have to be tight on gas like i do.

joys ally 5 cup setup he sells works really well.

Re: Lincoln T-355 1/4" alum tungsten balling

Posted: Thu Aug 19, 2021 1:25 pm
by alex.paap
Thanks tweake and toggatug,

a lot of good info coming from you guys. Once the 1/8" lanths come in I'll give the higher amps a shot.

The 3/32 holds up ok if the torch is vertical but holding at a 45 for the fillets causes the ball to start to drift off to one side.

I'll hunt around for the paper version of the weld calculator. If anyone's got a link to a .pdf that'd be rad!!

I think I can call this issue solved. Thanks again to everyone that helped out

Re: Lincoln T-355 1/4" alum tungsten balling

Posted: Fri Aug 20, 2021 10:24 pm
by Toggatug
No problem I like to be able to give back to this forum when and where I can since I've gotten so much out of it on my own journey of learning to weld.


As one little side note, I find even the 1/8 electrodes gets deformation when your north of 275 amps.

Takes longer than the 3/32 but I find after a larger job my tungsten looks like broccoli, I've never tried a 5/32 tungsten to see if that's the answer or if just a by product of the not so clean aluminium I get the pleasure of welding so you might be just fine with a 1/8 I'd be curious to know to be honest.

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Re: Lincoln T-355 1/4" alum tungsten balling

Posted: Sat Aug 21, 2021 4:43 pm
by BugHunter
I have a Dynasty and Miller says very specifically, do not use pure tungsten with an inverter machine. At least not their inverter machine. Not sure if that applies to all brands, but 2% lanth is all you need.