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Re: Lanthanated vs Thoriated

Originally Posted by Willie B

I don't think it works badly, only that there is no advantage over other alloys. And Dynasty is inverter, but can be switched to sine wave. I can't think why I'd want sine wave, square works better for aluminum. 280 places more heat in the weld than 310 from my Dialarc, etching is more effective.

You keep saying, "... other alloys". Tungsten is not an alloy, pure tungsten is also not an alloy for obvious reasons. Lanthanated, thoriated tungsten are alloys. Tungsten also known as Wolfram (W denotes tungsten on periodic table) has the highest melting point compared to any element. The thoriated doped tungsten alloy raises the melting point of pure tungsten. I suspect other alloys do the same but I've only researched the thoriated type in the CRC handbook of chemistry and physics. That's where I got my information should you decide to verify.

Also, tungsten is used in incandescent light bulbs because of its melting point and hi resistance after electrons flow. In other words; Tungsten is a dead short at first but the resistance goes up and then limits current.

Re: Lanthanated vs Thoriated

Originally Posted by G-ManBart

I really don't think it's a square wave issue as much as it is an inverter issue with pure tungsten. Pure works just fine with square wave transformer machines, just not inverter machines (all of which offer square wave as far as I know).

I generally only buy 2% lanthanated now, but I've welded aluminum on AC with pure tungsten on every Syncrowave I've had (17 and counting) and it works just fine....zero issues. I briefly had a Lincoln Square Wave TIG 175 and it was fine on AC with pure as well. Sometimes 2% lanthanated or a tri-mix would be noticeably better, but not always.

I actually like pure for testing a "new" transformer machine because you get to run DCEP to blunt the pure tungsten which lets you check that function works properly so you save a step. Pop in a fresh pure tungsten, blunt the tip on DCEP, then run AC on aluminum.

I don't think it works badly, only that there is no advantage over other alloys. And Dynasty is inverter, but can be switched to sine wave. I can't think why I'd want sine wave, square works better for aluminum. 280 places more heat in the weld than 310 from my Dialarc, etching is more effective.

Re: Lanthanated vs Thoriated

Originally Posted by Willie B

Best I can say, use pure to weld aluminum if you have a sine wave welder (transformer, except Syncrowave). If you have a square wave welder, don't choose as first preference for AC pure tungsten, You'll be happier with something else.

I really don't think it's a square wave issue as much as it is an inverter issue with pure tungsten. Pure works just fine with square wave transformer machines, just not inverter machines (all of which offer square wave as far as I know).

I generally only buy 2% lanthanated now, but I've welded aluminum on AC with pure tungsten on every Syncrowave I've had (17 and counting) and it works just fine....zero issues. I briefly had a Lincoln Square Wave TIG 175 and it was fine on AC with pure as well. Sometimes 2% lanthanated or a tri-mix would be noticeably better, but not always.

I actually like pure for testing a "new" transformer machine because you get to run DCEP to blunt the pure tungsten which lets you check that function works properly so you save a step. Pop in a fresh pure tungsten, blunt the tip on DCEP, then run AC on aluminum.

Re: Lanthanated vs Thoriated

Originally Posted by G-ManBart

Okay, that makes sense....inverters definitely aren't friendly to pure tungsten. I'm pretty sure that any machine, regardless of inverter or transformer that has adjustable AC balance has a square waveform, which was why I asked...but there's lots I don't know so it had me wondering!

Pure tungsten is different only in the shape of the tip. It melts to liquid easier than any other alloy. Pure rounds, then pretty much maintains that shape. All alloys are better able to hold a point, but as they degrade they take on unacceptable shape. Some tend to splinter, sending bits of tungsten to contaminate the weld.

Best I can say, use pure to weld aluminum if you have a sine wave welder (transformer, except Syncrowave). If you have a square wave welder, don't choose as first preference for AC pure tungsten, You'll be happier with something else.

Many very experienced welders prefer thoriated, others shy away because of a low level of radiation. They say lanthanated is as good. I hear some love tri mix (there are at least 10 manufacturers each has there own name for tri mix). Then there are the zirconated, and ceriated fans. I've tried all of these, I prefer thoriated, it costs less.

Re: Lanthanated vs Thoriated

Originally Posted by G-ManBart

Okay, that makes sense....inverters definitely aren't friendly to pure tungsten. I'm pretty sure that any machine, regardless of inverter or transformer that has adjustable AC balance has a square waveform, which was why I asked...but there's lots I don't know so it had me wondering!

I wonder if Syncrowave was a patented design. Airco marketed obviously rebranded Miller machines. I know of Syncrowave, when I started asking questions about the best aluminum TIG, every answer from everybody with experience was Syncrowave. The Dynasty series was new, and nobody believed a lunchbox could deliver the way Syncrowave did. I bought a couple of unsatisfactory welders. That's when Dynasty 280DX hit the market. It was close in price then to the Syncrowave, and its power appetite was smaller.

While it was a lot of money, I've never regretted the cost, it is a great welder supported by a great company. There have been a few times I wish I had gone with a 350, but helium has stretched the capacity.

Re: Lanthanated vs Thoriated

Originally Posted by Willie B

Inverter square wave, (I don't know about Syncrowave) since the ionization isn't lost as electron direction changes you don't need as much electrode positive to provide cathodic etching. This means less heat focused on the tungsten. An alloyed tungsten will retain a point better, where a pure tungsten will round quickly.

I misspoke that pure tungsten is useless. Not useless, it just doesn't give as focused an AC arc as alloyed.

Okay, that makes sense....inverters definitely aren't friendly to pure tungsten. I'm pretty sure that any machine, regardless of inverter or transformer that has adjustable AC balance has a square waveform, which was why I asked...but there's lots I don't know so it had me wondering!

Re: Lanthanated vs Thoriated

Originally Posted by Willie B

You can't adjust balance in Dialarc, but you can't make do with less than 50% EP anyway, the aluminum won't clean itself.

Sure you can. With clean aluminum, I sometimes go down to about 1/3 EP.

On a machine that only does 50-50 balance, you're going to lose some of the EP on clean aluminum, anyway, due to arc rectification.

Re: Lanthanated vs Thoriated

Originally Posted by G-ManBart

I promise I'm not asking to be argumentative, but I don't understand that statement....what model welder are you using?

My Syncrowave is square wave and works fine with pure tungsten (I've had multiple examples of Sync 250 from the first year up to just a few years old, so it can't be a coincidence). I'm certainly not an expert, but I have seen where some folks think that all transformer TIGs are sine wave, and that's not always true. If it has adjustable balance, it's square wave as I understand it (and I'm sure I'll be corrected if that's wrong!).

Inverter square wave, (I don't know about Syncrowave) since the ionization isn't lost as electron direction changes you don't need as much electrode positive to provide cathodic etching. This means less heat focused on the tungsten. An alloyed tungsten will retain a point better, where a pure tungsten will round quickly.

I misspoke that pure tungsten is useless. Not useless, it just doesn't give as focused an AC arc as alloyed.

I had a Dialarc 250HF. It was 60 cycle, sine wave. These machines are fixed at 50% EP balance. Pure tungsten was deliberately rounded to broom handle shape as it'll do it by itself anyway. Mine came with a piece of copper You used DC EP to round the tungsten tip, then on AC welding aluminum it'd pretty much maintain its shape until I dipped.

Yes, I do have a Dynasty 280DX. When I first got it I was amazed at how effective cathodic etching is with this machine. I have literally made successful repairs on an aluminum truck body that had been used to haul asphalt!

If I understand, sine wave power peters out before it changes direction. Shielding gas must be ionized before an arc reestablishes This ionization caused by a build up of free electrons concentrated on the tip of a tungsten electrode happen easily in EN half cycle.
Return half cycle, where electrons arc from a wider surface, maybe from oxidized aluminum, won't reestablish as easily. High frequency helps maintain the ionization making shielding gas more conductive, but not as effective as square wave that reverses instantly without losing the arc mid cycle. You can't adjust balance in Dialarc, but you can't make do with less than 50% EP anyway, the aluminum won't clean itself.

Re: Lanthanated vs Thoriated

Originally Posted by albrightree

I think Willy has a Dynasty 280 which I think is an inverter. I don't think they recommend the Pure tungsten (green) with the inverter machines.

hth

They definitely don't recommend pure tungsten with inverters, so that might make sense...and that machine is definitely an inverter.

Re: Lanthanated vs Thoriated

Originally Posted by Willie B

Yes & years ago Shovelon suggested I get a gas flow meter that reads at the torch. I was surprised to learn I was quite far off using the flow meter at the regulator.

If you use a ball-style, flow valve it gives an accurate reading of the flow.

Sincerely,

William McCormick

Re: Lanthanated vs Thoriated

I think Willy has a Dynasty 280 which I think is an inverter. I don't think they recommend the Pure tungsten (green) with the inverter machines.

hth

Re: Lanthanated vs Thoriated

Originally Posted by Willie B

My present welder is square wave, pure tungsten is useless, otherwise I'd use any variety, just have to grind more often.

I promise I'm not asking to be argumentative, but I don't understand that statement....what model welder are you using?

My Syncrowave is square wave and works fine with pure tungsten (I've had multiple examples of Sync 250 from the first year up to just a few years old, so it can't be a coincidence). I'm certainly not an expert, but I have seen where some folks think that all transformer TIGs are sine wave, and that's not always true. If it has adjustable balance, it's square wave as I understand it (and I'm sure I'll be corrected if that's wrong!).

Re: Lanthanated vs Thoriated

I'm not welder enough to say whether Lanthanated or Thoriated is better on aluminum square wave welding. To my observations they are identical when first dressed. Which degrades faster? I'll say lanthanated behaves more like pure would on sine wave power. It blunts quicker, but is less likely to splinter. Thoriated maintains its point, but tends to splinter.



That said, a beginner dips tungsten often if they hold a tight arc. When I began I bought a LOT of NOS thoriated pretty cheap because it is radioactive, and some don't trust it. Most of the online sellers didn't know what they were selling, none understood Thoriated, most were women, ALL had inherited tungsten from a deceased relative. I guessed these were hoarders who had stolen stock from their employers over 40 years. I remember one lady had thousands of boxes of 1/16 Thoriated, but only a dozen or so of 3/32".

My present welder is square wave, pure tungsten is useless, otherwise I'd use any variety, just have to grind more often.

Re: Lanthanated vs Thoriated

Awesome!

Re: Lanthanated vs Thoriated

Just a followup, I lowered the pressure yesterday and finished up the run (only a few inches) without any noticeable difference. I received the new electrodes today and swapped the lanthanated for the thoriated and just now did a few inches and its all good! The puddle worked smooth as silk, I could move it around and the filler blended right in and I didn't have to concentrate as hard, I could relax and just do the weld.

Re: Lanthanated vs Thoriated

Originally Posted by G-ManBart

PSI or CFH?

What size cup? 20CFH is really only needed with a large cup. Take the cup size and double it for a ballpark setting.

Yes & years ago Shovelon suggested I get a gas flow meter that reads at the torch. I was surprised to learn I was quite far off using the flow meter at the regulator.

Re: Lanthanated vs Thoriated

Originally Posted by ojh

I just checked, it was lower than I thought, about 20psi

PSI or CFH?

What size cup? 20CFH is really only needed with a large cup. Take the cup size and double it for a ballpark setting.

Re: Lanthanated vs Thoriated

Shovelon is working with you, I got nothing he won't say, but wander, once bridged is unheard of. You need to focus the arc at the leading edge of the bridge. You may find it works for you to dab filler without retreating 1/32" with the arc, or you might find it best to advance the arc, then retreat while dabbing filler.
Once the puddle bridges the gap the arc is on the leading edge of the bridge.

Re: Lanthanated vs Thoriated

I just checked, it was lower than I thought, about 20psi

Re: Lanthanated vs Thoriated

No high speed pulse, I have an old analog machine, Miller 350A/BP and been welding like this for a while. I just find it odd the puddle will pull back to either side of the seam (tight joint, in contact enough to do fusion weld) but the two sides kinda draw back, I add filler to create the puddle but acts like it wants to chose one side or the other, very odd. Same filler I been using ER70S-2, same sheet metal, just all kind of normal stuff acting abnormal.
I have had a problem with my flometer and have the pressure on the high side, over 30? perhaps? Maybe I'm blowing the puddle apart?

Re: Lanthanated vs Thoriated

The lanthanated tungstens should work well provided you keep it dressed as it does not hold up quite as long as thoriated. And horiated will splinter a tad when eroding and will still strike a sharp arc on start. However lanthanated is superior for AC welding.

I also sharpen mine razor sharp as opposed to the dulled(blunted) style. The dulled point allows more arc wandering for me and I hate that. As far as the rod, that should not be a problem in my mind.

Do you have high speed pulse? The puddle agitation from the pulse will help join the seam.

Lanthanated vs Thoriated

I normally use 2% Thoriated when welding 18 & 20ga 1024 sheetmetal and ordered 2% Lanthanated by mistake. I've been trying to use it and am having problem with puddle flow, when adding more filler it acts as if it won't join up in the puddle. Is this due to the rod?
I have more thoriated coming but would like to know if that is the problem. I'm using .045 -2 filler rod.
Thanks, Oj