[weldin mike 27]

Check your inbox /out box. Won't send if full

[Bill Beauregard]

It says 0%, 3%,and 5% full. I'm confused, computer troubles are beyond me. I don't understand, and I'm not even blond.

[Bill Beauregard]

It says 0%, 3%,and 5% full. I'm confused, computer troubles are beyond me. I don't understand, and I'm not even blond.

[weldin mike 27]

Right. That's not the problem. Moving on. Tappatalk or computer browser

[soutthpaw]

DCEN. Also had a really strange haze cloud around the puddle that makes it much harder to see than AC argon TIG. Usually the black "soot" that forms on the puddle on DC makes it hard to see the toes of the weld as well no matter how much you clean it. Ar/He mix on AC can give the benefit of both worlds.

[tekmachinewerx]

Can i still weld as u are saying with a footpedal that is just on and off. Not adjustable. I not to weld aluminum and im saving for a acdc tig. But right now i have jobs that require aluminum welding. It just welding in holes on thick aluminum. So can i use 200amp dc tig with 98% hel 2% argon was it 25-35psi
so run down on questions
can i still do this with off, on foot switch
do i round or point tungsten
green or red
and thank you for ur time

plz guys dont post anything about im stupid or whatever that crap i ask question because i need to know.
sorry some forums i get called names because i dont know simple things

[Superiorwelding]

tekmachinewerx,
Welcome to the forum! You will NOT be out down for your level of knowledge here. We all started on the bottom. Those are great questions and I want to try an prod a few members that have a little more experience at DC tig than me to answer.

When you find time go introduce yourself in the Member Introduction section!
-Jonathan

[Braehill]

Tek,
You say that you need to fill holes in thick Aluminum and this can be done on DC but will require you to use a very heavy electrode. 200 amps is not a lot of amps while welding Aluminum. If you said that you were trying to fill holes in thin plates, I would say that you'd have a better chance at a positive result.

How big are the holes? Can you get down in there and put more than 1 pass? A picture of what you're trying to do would help. More info will get you more help. This may be something that you're not able to do but we can't tell yet with the information provided.

As Jonathan has said, you'll not be put down for any question here or that person will be gone post haste.

Len

[Bill Beauregard]

I've only experimented with aluminum DC-. I was welding two 1/4" plates together. It was prepped well, 2 35Degree bevels, 1/8" land, 1/16" apart, copper backer. 1/8" thoriated tungsten 15 cfh argon. I needed a large puddle that was beneath a skin of dull grey crud. I could push filler through the skin to fill. It was in flat position, wasn't pretty on the surface, but cleaned up reasonably well with Norton Blaze on a 4-1/2" grinder. I'm concerned that if your holes are not the right ratio the "Skin" won't float up as you fill. if they are too big and you have to werd in concentric rings to fill, they certainly won't clean enough to bond. I think this is a project to farm out if you aren't equipped. Better to say to a customer I'm not equipped, than screw it up.

[DeweyO]

Tek -
How thick is thick? 1/4"? 1/2"? A full inch? You could easily use 200A on 1/4" Al. but the diameter of the hole is a big factor too. An inch hole in 1/4" plate would take less amps initially. This is where the progressive foot pedal shows its worth. If you're just looking for on & off, you might just as well be scratch starting, a technique used for decades before foot pedals. (Like when it was called heliarc).

[RocketSurgeon]

I've gotten into this debate many times with younger welders right out of school all the way up to welders twice my age and experience. The debate about TIG welding Aluminum on DC. They all say you Can't do it! One thing I've learned in my 15 years in welding is there no such thing as Can't in this industry, you just don't know how. So, figured I'd post something about it and see what all you welders around the world have to say.

Here is the recipe I like to use...

Set machine for welding Steel no more than 190-210 amps regardless of thickness, need a foot pedal for this
Standard or gas lens set up (Gas lens is a bit cleaner but not needed)
2% tungsten works fine 3/32-1/8 sharpened
4043 rod 3/32 (depending on thickness of course)
25-30 psi of Helium (use the helium to bump up the heat not the amps)
5 psi Argon (helps clean up the weld a bit but also not always needed)

A few Pros and Cons

Pros...

-Don't have AC and need to weld aluminum!
-No Preheat for thick parts
-Makes for a great small root pass (preheats for the cap) or one large pass
-Burns much hotter so you can get in and out with minimum warpage but still getting good penetration

Cons...

-Dirty looking weld (until you figure out the right angles). If the material is dirty it really shows in the top and bottom of the weld (as in the photo) but comes right off with a wire brush. This was just handles for a base plate so didn't need to clean up nice.
-Wire will ball up very easy if not added properly. It's not forgiving so add it in the right spot
-Uses a lot of Helium which isn't cheap but if you're welding of a machined billet plate that can't warp too much...


Anyone else ever try this? If not give it a try.

Our recipe:
DC- (reverse polarity)
115-135~ amps, depending on thickness
Pure, dry He @20cfm
2% Thoriated electrode
#7 cup
2sec lead in
5sec lead out

[MinnesotaDave]

RocketSurgeon - you've got a typo:

DC-, DCEN, straight

DC+, DCEP, reverse

[RocketSurgeon]

RocketSurgeon - you've got a typo:

DC-, DCEN, straight

DC+, DCEP, reverse

Whoops. You are correct, sir.

DCEP is the polarity we use.

[MinnesotaDave]

RocketSurgeon - you've got a typo:

DC-, DCEN, straight

DC+, DCEP, reverse

Whoops. You are correct, sir.

DCEP is the polarity we use.

That's awfully hard on the tungsten - and pure argon works well on DCEP, why spend the money on helium?

Normally people use 100% helium on DCEN for deep penetration.

[RocketSurgeon]

It's what we use at work because of the alloy. 2219 and 2195. 2% Thoriated keeps a nice focused arc and the He keeps the parent material hotter without cranking up the Amps.

Add the rest of the recipe and we can keep the weld clean without AC or a wandering arc. We have to for the customer.

[MinnesotaDave]

What thickness are you welding with 135 amps DC+ (DCEP) and pure helium?
What size tungsten?

[RocketSurgeon]

What thickness are you welding with 135 amps DC+ (DCEP) and pure helium?
What size tungsten?

.625" 2219 parent with 2195 plug. 3/32" tungsten. 2319 filler.

[MinnesotaDave]

What thickness are you welding with 135 amps DC+ (DCEP) and pure helium?
What size tungsten?

.625" 2219 parent with 2195 plug. 3/32" tungsten. 2319 filler.

Then respectfully, I think you are confused about polarity.

Over 1/2" thick material, and only 135 amps, 100% helium, no wandering arc - this says DC-, DCEN, straight polarity to me.

[RocketSurgeon]

Ground clamp on the negative leg, torch on the positive (our symbol for this is DC-). We work to WPS that has been used for a couple of decades and approved by our customer: NASA.
These are high grade parent materials that must have 0 porosity and 0 inclusions and 0 contamination.

We've been doing this technique for a while. We don't follow AWS or ASME standards and specs. We follow MilSpec and NASASpec.

[MinnesotaDave]

Ground clamp on the negative leg, torch on the positive (our symbol for this is DC-). We work to WPS that has been used for a couple of decades and approved by our customer: NASA.
These are high grade parent materials that must have 0 porosity and 0 inclusions and 0 contamination.

We've been doing this technique for a while. We don't follow AWS or ASME standards and specs. We follow MilSpec and NASASpec.

Again, respectfully, there is some confusion somewhere, DC-, DCEN, DC electrode negative, straight polarity.

Are you saying that NASA and the military labels these backwards from welding industry standards?

I guess I would not be surprised

My torch and work clamp do not get switched around either - I use the selector on the machine to set DC-, DC+, or AC.

When I select DC- my torch is negative, therefore I am welding DCEN, straight polarity.
When I select DC+ my torch is positive, I am welding DCEP, reverse polarity.

Do you suggest that I am incorrect?

[RocketSurgeon]

Mil and NASA specs can be niche techniques that only apply to one or a few applications. The R&D can take years (or sometimes by chance). I've seen overkill work that would be completely unnecessary in the public world, but makes total sense to NASA.

We build man-rated space flight vehicles. Their argument that overkill is necessary is rarely debated, let alone argued.

I completely understand your questioning about the nomenclature used here and the techniques. It isn't the typical AWS or ASME when it comes to the vehicles. It's their own. When all you see is their symbolism and terminology every day, you can not only confuse others, but yourself as well.

[MinnesotaDave]

Mil and NASA specs can be niche techniques that only apply to one or a few applications. The R&D can take years (or sometimes by chance). I've seen overkill work that would be completely unnecessary in the public world, but makes total sense to NASA.

We build man-rated space flight vehicles. Their argument that overkill is necessary is rarely debated, let alone argued.

I completely understand your questioning about the nomenclature used here and the techniques. It isn't the typical AWS or ASME when it comes to the vehicles. It's their own. When all you see is their symbolism and terminology every day, you can not only confuse others, but yourself as well.

You didn't answer the question actually - does NASA and the military label their stuff backwards from the welding industry?

When I select DC- my torch is negative, therefore I am welding DCEN, straight polarity.
When I select DC+ my torch is positive, I am welding DCEP, reverse polarity.

DC+ will melt a 3/32" tungsten super fast.
DC- works great with a 3/32" tungsten.

I am not confused by what I have said.

[RocketSurgeon]

I know for sure that NASA does. They consider the ground clamp as a constant. Everything is based off the ground.

[wheresmejumper]

Ground clamp on the negative leg, torch on the positive (our symbol for this is DC-). We work to WPS that has been used for a couple of decades and approved by our customer: NASA.
These are high grade parent materials that must have 0 porosity and 0 inclusions and 0 contamination.

We've been doing this technique for a while. We don't follow AWS or ASME standards and specs. We follow MilSpec and NASASpec.

I didnt know that different laws of physics apply to NASA and the military?!
0 porosity 0 inclusions etc is a pretty common requirement,even down here on the earth.and away from the front line too.

[DeweyO]

From the limited experience I've had using DC on Al. I would have to support Minnesota Dave. I've personally experimented on Al. castings and found DCEN works surprisingly well. The weld although dirty does clean up easily and full penetration is attained. In my case I used Argon only as that's all I had, and after all, I was experimenting. Basically, I treated the whole job as if it were steel.