what is a gas lens?

Dumb question: What is a gas lens?
I just bought a used TIG welder, and when I went to buy new tungsten, I saw a listing for a gas lens. It seems to consist of a collet and cup - is this
it? I understand that it is supposed to make the shielding gas flow more smoothly, is that correct?
I also saw a Pyrex cup. Is this helpful? Do they make a gas lens in Pyrex? My torch is a 17, hooked up to a Daytona Mig/Cebora Pocket Pulse 100.
Thanx!
--
__
"All it took was all I had..."



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From: http://www.arc-zone.com/Flat/glossary/TIG.html
Gas lens collet body- a special type of TIG (GTAW) torch collet body designed to provide improved shield gas coverage of the weld zone. Typical gas lens construction consists of a series of coarse and fine screens placed around the electrode. This construction provides optimum laminar gas flow which reduces the possibility of drawing in contaminants from the surrounding atmosphere. The use of a gas lens collet body allows further extension of the electrode beyond the gas cup, improving weld joint access and welder visibility. Gas lens collet bodies are required to achieve optimum weld integrity on non-ferrous, or oxidizing metals, such as aluminum.
Emmo wrote:

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Would a gas lens also be useful for steel and stainless ?
Thanx for your response and the pointer to the glossary
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Emmo,
I can't say as I've never used one. I'll have to defer to the experts here.
However, let's look at the complete definition again:
"Gas lens collet body- a special type of TIG (GTAW) torch collet body (1) designed to provide improved shield gas coverage of the weld zone. Typical gas lens construction consists of a series of coarse and fine screens placed around the electrode. (2) This construction provides optimum laminar gas flow which reduces the possibility of drawing in contaminants from the surrounding atmosphere. The use of a gas lens collet body (3) allows further extension of the electrode beyond the gas cup, improving weld joint access and welder visibility. Gas lens collet bodies are required to achieve optimum weld integrity on non-ferrous, or oxidizing metals, such as aluminum. " [ numbers are mine ]
I numbered three things. If it does all those I expect it just might help with any type metal. (1) provide improved shield gas coverage of the weld zone. (2) reduces the possibility of drawing in contaminants. (3) Allows further extension of the electrode beyond the gas cup, improving weld joint access and welder visibility. They are "required" on non-ferrous metals - in order to achieve optimum weld. Therefore, I'd suspect it will definitely help on ferrous metals!
But, again, I'd rather hear from someone who has done it both ways! :-)
Al
===========
Emmo wrote:

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Yes, yes, yes.
url for CK Worldwide: http://www.ckworldwide.com /
Ciao and best, David Todtman
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Lens: collet, collet body, and cup system that causes the shielding gas to flow in a well-formed stream. You get to use a little less gas and, best of all, you get to stick out the tungsten really far which is a great thing. My own experience is that changing from the standard cup system to a gas lense is WAY worth the small expense and trouble to figure out what you need. Figuring this out was confusing at first. First, I read some very helpful messages here on the topic. That's why your question is FAR from dumb! What I did next was call CK Worldwide--a Seattle-based company that makes torches, lenses, and other related products--and got them to send me their catalogues. (There are three--least, that's what it was when I needed to learn this stuff.) I studied the catalogues and then called CK (l.d. from Vancouver Island) and asked questions. They are happy to respond and did not speak down to this neophyte. I've called them other times and got consistently positive help.
Pyrex cup: Have not used such. Ernie will, no doubt give you his comments, which I think will include something like the cup is clear and you get to see better. I'm not sure what welding situations would really benefit, though. Probably working in corners.
Ernie: when do you use Pyrex lenses?
IMHO, everybody should get gas lense systems (collet, collet, body, cup) for all tungsten sizes they weld with. I cannot imagine how a person would be sorry.
With all good wishes, David Todtman

saw
this
Pyrex?
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CK "Gas Saver" gas lenses have the option for pyrex cups. I have used them and they are quite fragile.
The only CK GasSavers that I use the pyrex cups on is my HUGE #2 series 1-1/4" ID gas saver. CK invented them for titanium welding and they work really well for stainless steel sheet metal seams.

They do allow good visibility of the weld, but they are quite delicate.

I think the standard gas lenses are more practical than CK Gas Savers. BTW I pretty much stick with the #8 gas cups for everything.

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My first use of a gas lens was a CKW gas saver with a ceramic cup. That was the period in tig 'career' that the weldment exerted such magnetic force that it my drew tungstens into the weld as fast as grass goes through a goose. The screen on a CKW regular gas lense is deep within the cup but on the gas saver it is right at the end of the cup. Well, as soon as I pressed the foot pedal that magnetic force whipped the tungsten right into the weldment and, blam, molten metal burnt about a quarter of the screen away. The screens are attached to the collet body. So, scratch one collet body _before_ I even had a chance to start a bead. From my experience, I agree that the regular gas lenses are more practical than the CKW Gas Savers.
Ciao, David Todtman
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