TIG welding help

[fusername]

In order of importance:

is there anything I could be doing wrong to make my arc shrink? when I am welding, sometimes part way thru the weld the arc will diminish as if I have let off the pedal, but I know i haven't. It .could. be the machine, but I am blaming myself first.

tips on welding square tube to square tube? since it has the rounded off edge, there is that small valley to fill. MIG would love it, but I am trying to teachmyself TIG right now. Should I prep the tube somehow, lay some filler rod and include it in the weld, change my technique? I assume technique.

thanks guys! Reading everything I can about tig these days.

[Chris4747]

I cant think of anything that you could be doing wrong. whats the cool down time on the machine ? is the machine on 220 or 110? if its running on 220 check to see if you are running on only one leg .

[fusername]

220, so I will double check both legs are hot. The issue is intermittent, and I have only welded a few minutes total at this point on this machine, so I really hope it is me. Intermittent electrical issues are horrible!

[Chris4747]

Sorry wish i could help but if your not pulling off the weld and your getting power it might be internal on the machine You could try a new ground wire to your work ,you could have a broken wire thats getting jostled around and loosing conction good idea to chek the peddal/roller trigger wires to

[fusername]

I'll look into my ground wire, I had a few non-starts just now that didn't make any sense. on the bright side where I work I bet I can have new ends put on for free!

[Piledriver]

Could be loose power lugs anywhere between you and the pole.

I'd start at the torch and work my way back.

OTOH my little 181i initially gave me absolute fits with TIG before I figured out you have to set one of the dials to zero or it goes to full dial current and tapers off for the dials set time automagically after you let go.
(it has 3 dials that do 5 different things, depending on mig/tig etc. I'm sure that's in the manual (looked, never found it) I fixed it by accident)

I guess the automagic upslope/downslope is a feature for folks w/o a pedal or such, but if you have one, make very sure all the upslope/downslope/spot timers are off or it will mess with your head, as it will do what it is programmed to, not what you think you are telling it to do.

Basically, if you don't know for sure what all the switches do, turn `em off.
(you have lots of them IIRC)

[aircooledtechguy]

Check the duty cycle of your machine. Most will shut down automatically when it gets too hot or when the duty cycle is exceeded. Maybe yours just scales back the power.

[Piledriver]

He has a massive Lincoln TIG 250 or 350, full features setup with a cooler, size of a small refrigerator.
(and a LOT heavier)

Those are ancient, industrial rated beast~100% duty cycle machines out to >150A.

They do have lots of function switces/spot timers/ramp up/down etc though.

[fusername]

this one sadly does not have all those features. Made in '61 it seems, I only have auto-fade out, but only when not using the pedal.

dumb question. I have coarse current adjustment with 5 positions, and then a fine adjustment knob w/ infinite sweep. the manual is vague on this. I know when I am not using the pedal control the fine knob sets the current. However when I am doing pedal control does the fine knob set the MAX current, or is it cut out of the loop all together?

hahahaha program, I odn't think there is an ounce of silicone in mine, except for the diodes! gonna pull the side panel and bring it to work, since the schematic is printed on it and I work at an electronics company now. the nerds there could look at it and in 5 seconds tell me exactly what every transformer is for.

[fusername]

My new baby! almost no features aside from HF start, but I like it. I might try putting an auto on/off on the cooling fan, since it is always on, but I am not doing production work, or anything over 100 amps, so I probably only really need it when my gas is running 90% of the time, and when I do heavy stuff I can just set it back to always on. Also thank you Pile for convincing me not to sell the water setup. I have 0 issues w/ the heat n the air cooled line, but in the cold weather that cable is STIFF. My space is unheated and when its 20deg out you can't bother trying to use it, even when its 40 you have ahard time controlling hte tip.

As for the fade out, I foudn a good way of ruling out the foot pedal bing the issue. I will use the current control on the machine, and turn the auto-taper out on. If it behaves fine all day, I'll blame the pedal. Otherwise I will swap out to the air cooled torch to rule that out second.

[fusername]

look at how much i overheat the metal! is that bad or terrible? trying to get a sense of how far off I am, gonna do a whole bunch of welding today.

[fusername]

Good news, its the pedal or pedal controlls, when I turn them off, problem goes away. Now I just need to wrestle the damn thing away from the column (that pic is from the PO) so I can pull off the side panel and check all the connections.

[Piledriver]

look at how much i overheat the metal! is that bad or terrible? trying to get a sense of how far off I am, gonna do a whole bunch of welding today.

You must have missed the memo about "clean"

Argon does ZERO cleaning, the HF does a little if you leave it on, but that's not the right idea.
(AC cleans on 1/2 the cycle, but you don't want to do AC unless you absolutely must, esp on a sinewave machine w/no balance control, it's like doing detail work with a little kids giant crayon)

To get those perfect TIG welds, (or even welds that don't look like total ass) CLEAN is the first step.
Prep in general is the rest of the trick--- Its like a paint job, 95% of the trick to good results is excellent prepwork
(CLEAN and FIT)

Having said that a real artist will make it look good anyway, or start over until it does.

Watch the PUDDLE, not the arc.
Puddle control is 90+% of the art, much like gas welding.
(same is true for MIG but you are usually going too fast so you use the machine settings to get it ~right)

My welding sucks too. I don't do enough.

[fusername]

now I have been wiping it down w/ acetone as a clean step. I assumed since it was fresh metal there is less of a need to sand it down prior to working, am I wrong in that count? above is probably my second worst weld of the day (the one where the tungsten melted into the puddle came out worse, belive it or not...) but the best do't look much better.

practice practice practice

[aircooledtechguy]

Be VERY careful when using ANY kind of solvent to clean the metal before you weld. Some like brake cleaner create Cyanide gas and will KILL YOU or leave you dumber than a post hole digger.

To clean a part, all you need is a grinder with a wire wheel on it OR a hand held wire brush. Often times bulk steels like angle iron for example, will have an anti-corrosion oxide coating that can cause your welds to not come out as planned. A quick pass of the wire wheel, 3" sanding disc, or a wire brush will remove it and greatly improve the weld quality.

Nice thing about welding with a TIG is that if it looks like a bird took a crap on your project or if you didn't get enough penetration, simply go back over it with the torch and allow the puddle to sink (adding penetration) along with a little more filler rod and VIOLA!! Your welds look like a pro (or at least like the bird had diarrhea and it's stuck really well ).

TIG takes practice and welding is NOT like riding a bike. You loose it with time.