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KenK
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First, I would like to say thanks for the excellent videos posted on this web site. They are the best I have seen. You can actually see the puddle not just a bright over exposed light which is not really helpful.


In viewing a number of the videos on this site, I noticed that in a large number of them gas lenses and large diameter cups were being used. What is the advantage of the use of the "Gas Lenses" and large diameter cups?? In my case, I work with a lot of tubing and in tight spots and the large diameter cup would be a problem.

During a visit to a local weld shop, I compared the length of the standard cup with a gas lenses, large diameter cup system, and found them to be pretty close in overall length.

I tried to do a search for the subject on this forum but did not come up with a workable list of posts on the subject.

Any help on the subject would be greatly appreciated.

KenK
cj737
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    Thu Sep 29, 2016 8:59 am

A gas lens comes in handy with larger than a #5 cup for promoting less turbulence and better coverage in the gas. Large diameter cups offer greater coverage and almost depend upon a gas lens to be effective (and higher flow rates). With a larger cup, you can run a longer stick out and get the tungsten tight even in cramped joints, something you can’t always do with a smaller cup.
Mike
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Welcome to the forum, Ken.
M J Mauer Andover, Ohio

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KenK
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Thanks for the acceptance and the replies.

I am not a pro by any means and for the most part do not get paid for my work. I due work a lot with tubing though and some of the joints are hard if not impossible for me to get welded. I can do better with MIG because you can let the wire go out a ways and usually get a decent weld (not good but decent).

I bought the TIG machine (a Miller Diversion) to allow me to work with SS and Aluminum. I also found that TIG machine allows me to weld on very thin steel (22 and 24ga) which I do quite a bit of (an added benefit).

I recently had a project where I needed to weld between 2 pieces of 3/4" square Aluminum 1/16" wall tubing spaced about 1/2" apart. I welded the first piece in and welded it on all four side. I welded the second second piece in and welded it on three sides. When I tried to do the weld on the second piece between the two tubes, NO LUCK. Gas and heat control was the problem. I gave up before I made a mess. I was using a #6 cup and a 1/16" tungsten with a gas flow rate around 20 LPM. I did not try to use a gas dam on the back side. I will mock up a similar situation on some scrap tubing and see what I can do soon. I need to master this scenario.

As a suggestion: A short video on the use of, selection of and suggested gas flow rates for the use of larger cups and gas lenses would be helpful for us beginners and help promote gas lenses, cup sales.



Again, thanks for your help. GREAT WEBSITE!!

Ken
cj737
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    Thu Sep 29, 2016 8:59 am

I’m that situation if arc length is the problem, then you need either a very small but long nosed cup, or a longer stick out and larger cup. You might also experiment with a larger tungsten too if amperage are higher.

Aluminum does not weld very well with a long arc. You really need to keep it tight.
dgapilot
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Not experienced enough to really know, but from the videos, you can use a longer stick out with a gas lens and larger cup. While you may not be able to get as close with the larger cup, the longer stick out combined with less turbulent gas flow and higher flow rate lets you get into the tighter joint.


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David

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KenK
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Thanks for the input.

In this case I was working with 1/16" wall Aluminum tubing so the 1/16" tungsten was a good choice. As for the short arc, I have found that with alum, the shorter the arc the better. I may try a larger clear cup (so I can see through it) and an gas dam behind the weld to see if I can do any good. Getting the filler rod in also becomes a problem when doing this.

I need to work on fusion welding with aluminum as well. At this time, I cannot do this very well if at all. Once I master fusion welding on aluminum, I could make a pile of filler material between the two tubes and fusion weld the joint.

Thanks again for your commits.

Ken
cj737
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The Fupa cups comes in sizes 5,8, and a 12 and are Pyrex for such work. Even with thin walled tubing, sometimes a thicker tungsten helps because of the amperage required. Not always...

Fusing aluminum is fine for tacks, but it has no strength. When you have long stick outs and small filler, the heat effect from the shielding/surrounding area is tricky as it wants to burn back the filler before it reaches the puddle. You need to change the angle of attack with your rod and stab it in their quickly to avoid the melting back. (If that’s the problem you’re having?) but the gas lens and large cups do make it easier to get the filler in there without having to use a dam.
KenK
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Thanks for the input.

I just bought a stubby gas lenses, cup set for my torch. If nothing else, it will help me get the torch into tight places.

Thanks for your help.
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