[RichardH]

Difference is that argon is not being peacefully poured out of the TIG cup, it's being forced out under pressure in order to deliver a flow rate that ensures good coverage in spite of environmentals. The path of that flow generates its own turbulence, which the gas lens removes by getting everything flowing in the same direction at the same rate (laminar). This causes the stream to retain its shape for a much longer distance.

[dsmabe]

I understand many people use pressure gauges to determine their shielding requirements so maybe that is where some of this is coming from. But once the argon reaches the cup, it is no longer under pressure compared to atmospheric pressure. So in a sense it is "pouring" from the cup. Unless your like my coworkers who think more is better!

[RichardH]

I realize its a technical subject, so important to be precise with terms. Yes, the argon is ultimately exits the cup at 1ATM, but it's being forced out of the cup at a high rate and at a variety of angles, which generates turbulence. Which is what the gas lens is counteracting.

If you were to take a pitcher of argon and pour it through a #6 cup, gravity would not cause it to flow at the same 15CFH rate; that, combined with the lack of nozzle jets in the path, would yield low turbulence; but it would also be very fragile to environmental factors like the tiniest of drafts. The higher CFH helps overcome environmentals, but increases turbulence which the gas lens counteracts.

Using a more familiar example, water exiting a garden hose at a low flow rate will have a fairly glassy smooth surface, pointing down, that can be maintained for a good distance. Turn it horizontal, and it won't go far. Crank up the flow rate, and you can shoot it 20 feet, but it'll be turbulent and lack form. Put the same flow rate through a laminar jet, and it'll be glass-smooth for most of that 20 feet. Similar behavior with a gas lens.

[Braehill]

@ Steve,
I found this statement about the Reynolds numbers very interesting when looking through the original patent for a gas lens, and how it got it's name.

US 3,053,968

"When gas lenses are employed, coherent-streams can be produced regardless of the Reynolds numbers of L/De value which have frequently been used in the past as mathematical specifications for flow conditions. Our findings are that such numbers do not insure laminar or nonturbulent flow, but rather they indicate a possibility for laminar flow. In laboratory tests, it was possible to obtain coherent-streaming distances of 3 to 6 inches under conditions which would correspond to Reynolds numbers of the order of 5000 and L/De ratios equal to zero. At the present time, there are strong indications that coherent-streaming through appreciable distances can be obtained at Reynolds numbers at least up to 15,000 with the aid of gas lenses.

It 'must be noted, however, that the calculation of Reynolds numbers applies only to a gas stream cross-section within conduit walls. Hence, when permeable barriers or gas lenses are used without a downstream conduit, e.g., L/DQEO, then Reynolds numbers do not apply.

From these tests it is apparent that the use of a special class of permeable barriers results in a degree of control over gas flow patterns far beyond that which could be obtained with conduits or nozzles. This special class consists of devices made from permeable materials which produce a relatively smooth and continuous distribution of gas velocities, in terms of both magnitude and direction, across the downstream surface of the permeable material even when gas is supplied to the barrier in a state of gross turbulence. Since these permeable barriers act on gas in much the same manner as a glass lens acts in shaping a beam of light, the analogous term gas lens has been applied to them by us."

Len

[Otto Nobedder]

@ Steve,
I found this statement about the Reynolds numbers very interesting when looking through the original patent for a gas lens, and how it got it's name.

US 3,053,968

"When gas lenses are employed...

(seriously redacted)

From these tests it is apparent that the use of a special class of permeable barriers results in a degree of control over gas flow patterns far beyond that which could be obtained with conduits or nozzles. This special class consists of devices made from permeable materials which produce a relatively smooth and continuous distribution of gas velocities, in terms of both magnitude and direction, across the downstream surface of the permeable material even when gas is supplied to the barrier in a state of gross turbulence. Since these permeable barriers act on gas in much the same manner as a glass lens acts in shaping a beam of light, the analogous term gas lens has been applied to them by us."

Len

LIKE

Steve S

[dirtmidget33]

I'm really surprised by the doubts some have had over these pictures. Since some don't like the claims by the companies here is a video of Jody that compares gas lens and regular collet. Results gas lens=better gas coverage period

http://www.weldingtipsandtricks.com/tig ... -laps.html

As for arguing the mathematics its not even worth the effort really as I previously stated fluid dynamics mathematics gets confusing quick so this link will give you some of the equations if you really want to sort threw the crap and get a doctors degree in physics If that the case you can start here with these equations beginning with the formula are ready quoted previously.

http://en.wikipedia.org/wiki/Fluid_dynamics

Now to cut threw the bull to those that just want to weld. If you want better gas coverage get a GAS LENS they don't cost much more if we need to worry about that small added cost, we would all be wiping our bums with corn cobs to save on toilet paper cost


+1 Braehill Good Job

[dirtmidget33]

My previous post sounded a little harsh after I reread it. It was not meant to offend anyone so don't take it the wrong way

[Otto Nobedder]

My previous post sounded a little harsh after I reread it. It was not meant to offend anyone so don't take it the wrong way

Harsh?

Perhaps "passionate" is a better description.

We sometimes sidetrack into theory, and it can get deep, but your simple analysis of "Gas lens equals better coverage" cannot be disputed, wherever the math may lead.

Steve S

[TRACKRANGER]

My previous post sounded a little harsh after I reread it. It was not meant to offend anyone so don't take it the wrong way

Certainly no offense taken here. Robust discussion and the chance to receive multiple viewpoints from other experts makes for a better result, always.

[Otto Nobedder]

My previous post sounded a little harsh after I reread it. It was not meant to offend anyone so don't take it the wrong way

Certainly no offense taken here. Robust discussion and the chance to receive multiple viewpoints from other experts makes for a better result, always.

Okay, there's another "LIKE".

I'm seeing value in changing our "ranking" system from a "post count" to a quality-based system...

Just thinking out loud...

Steve S

[dirtmidget33]

Certainly no offense taken here. Robust discussion and the chance to receive multiple viewpoints from other experts makes for a better result, always.

I never claim to be an expert at anything. Matter of fact anytime someone claims to be an expert they loose me. To me an expert means you know every possible thing on a given subject including abstract variables. Therefore I don't believe anyone can be an expert just either experienced or knowledgeable of subject

[dsmabe]

My previous post sounded a little harsh after I reread it. It was not meant to offend anyone so don't take it the wrong way

Not offended here either.
I didn't completely agree worth a post, so offered my opinion. But long story short, I like using a gas lens, seems to have better coverage for me.

[Braehill]

@steve,
let's not go for quality, I don't want to be bumped back to new member

I for one think just because we've established a 50+ year old fact is no reason to being pat ourselves on the back.

Gas lens equal better gas cover, I've always agreed with that, but I still have a bin full of small standard collet bodies and small cups. Reason being, real estate, sometimes just being able to get to what needs welded outweighs the gas coverage factor. So I'm not ready to throw mine away just yet. A #4 gas lens is the same size around as a #10 standard cup at the top. Just another tool in the shed in my mind, they all have their place.

Len

[Braehill]

Just to let you guys know, the staging that takes place to make the gas flow visible is usually a fine oil mist added to the gas. It does change the density slightly but the flow characteristics should be consistent if they use it in both torches.

Len


Sent from my iPhone using Tapatalk

[TRACKRANGER]

Just to let you guys know, the staging that takes place to make the gas flow visible is usually a fine oil mist added to the gas. It does change the density slightly but the flow characteristics should be consistent if they use it in both torches.

Len


Sent from my iPhone using Tapatalk

Ah-haa!
Fine oil mist. Now we're getting somewhere. That really does makes sense. (And at the start I was thinking 'smoke and mirrors' - shame on me...)

[TRACKRANGER]

@steve,
let's not go for quality, I don't want to be bumped back to new member
...
Len

@len
Regardless of the way things are ranked, I somehow doubt your status would change, unless of course it went up!

[Braehill]

Ranger,
Thanks for the kind words.

Len

[rick9345]

Informative Discussion
Who ever thought Physics could be interesting,guess there was a reason in High school to pay attention
I use gas lens once I discovered benefits, There is/are still places only a regular will do(fit)[

[kiwi2wheels]

" if we need to worry about that small added cost, we would all be wiping our bums with corn cobs to save on toilet paper cost "

@ dirtmidget, you almost drowned my keyboard !

On a serious note, there have been occasions on aluminum where I have found it easier to control the puddle and edge burning by going from a #6 gas lens to a standard #5 cup. This was on inverter machines.

Anyone else experienced this or have suggestions why this is ? Thanks.

[dirtmidget33]

@ Kiwi2wheels this is just for you

1005141530[1].jpg (28.81 KiB) Viewed 2074 times

Dad always claimed that as kids they had to eat all the kernals off the cob so they could reuse the cob for butt wipes. He was full of it they never had to do this, but this year when the field was harvested I put this in his bathroom so he could relive his childhood.

[AKweldshop]

Anyone who's tig welded knows a gas lens is nicer for "SOME" things...

After that its all personal preference.

[AKweldshop]

" if we need to worry about that small added cost, we would all be wiping our bums with corn cobs to save on toilet paper cost "

@ dirtmidget, you almost drowned my keyboard !

On a serious note, there have been occasions on aluminum where I have found it easier to control the puddle and edge burning by going from a #6 gas lens to a standard #5 cup. This was on inverter machines.

Anyone else experienced this or have suggestions why this is ? Thanks.

Lots of guys tig alum with a #3 or #4 cup......

[Otto Nobedder]

I usually weld with whatever cup the last guy left on the machine...

Steve S

[kiwi2wheels]

Thanks for the replies gentlemen, one less thing to think about.

File under " Don't sweat the small stuff "

[DSM8]

I have been pretty much welding everything with a gas lens and a #6 cup.

AL
SS
Cold Rolled steel etc.

I find getting used to doing all thickness, shape and types of materials with one set up has contributed to my being a better welder since i have to work more on technique (stickout, angle material placement etc).

the most challenging welds for me so far have been on tubing, those are a bitch.