TIG Torch Cups & Gas Lenses question(s)

[G-ManBart]

I have both 3/32 and 1/8 tungstens. Is there anything wrong with using the 1/8 for lighter work as long as I use the appropriately sized cup
for the job?

Generally speaking that's fine, but there are times when it won't terribly work well. For example, if you're trying to weld at low amperages you might get an inconsistent start or the arc wandering. That just shows you're not really running enough amperage for the tungsten diameter. If you put a really sharp point on the tungsten it will help minimize the arc wander in situations like that. It seems more noticeable if you're trying to do something like an edge weld on thinner material....the arc just won't focus on the edge like you need it to be. If you can't sharpen the point enough to get a consistent start and no arc wander, then it's just time to drop a tungsten size.

 

[G-ManBart]

General Zod covered most of the things I was thinking, but I thought of a couple things that might be helpful.

These are just really broad generalizations, so nothing absolute.

Most people stick to roughly 2x the cup diameter for argon flow....so a #8 cup gets around 16cfh. If you use too high of a flow you can cause turbulence and get porosity. A gas lens will usually let you get away with a lower flow than a standard setup (other than the huge cups for stainless), but that's just a bonus, not the reason they exist.

For mild steel you can put a #7 or 8 cup on and pretty much forget about it until you're trying to get into small spaces. For aluminum you can stick with the #7/8 but at times you may like a #5 or 6 as it will decrease the cleaning zone and look nicer. For stainless you want as big a cup as you can get away with practically speaking.

Gas lenses are a great option and the only downside I can think of is that they're larger in diameter...not always an issue. Pyrex cups are fantastic in that not only can you see through them, but they also seem to reflect the arc light right back on the puddle so you can see better even when you're not looking through them. The downside to pyrex cups is that they can't handle as much heat as alumina cups (pink type), they're a bit more fragile and they cost a lot more.

I use alumina cups on gas lenses for the majority of my welding, but switch to the pyrex when they offer an advantage....a great option to have.

 

[7milesup]

Excellent points G-Man.

 

[General Zod]

I have both 3/32 and 1/8 tungstens. Is there anything wrong with using the 1/8 for lighter work as long as I use the appropriately sized cup
for the job?

Nothing wrong with it, but some machines have limited hot-start settings that will make arc initiation more difficult, even with a long, sharp taper. So I'd say it's quite machine-dependent.

Another downside of a gas-lens set-up is if you have an inadvertent draft, or shielding gas problem, even for a split second the molten pool can become so agitated with the presence of oxygen that it will spit up molten droplets of steel and it will instantly stick to and clog up your mesh screens on the gas lens. Which usually means it is ruined and is typically discarded. With a standard collet body set-up, the same is not always true.

 

[GunsOfNavarone]

At the end of the day, everyone bends the rules to get the job done. Long stick out is nice and it requires more gas. I hate buying argon, it’s expensive. I’m getting ready to buy a 376 cf tank so I just have to pay for gas going forward….not the tank as well.
Here’s my 9 torch but can flip flop to a 17 as well (series 2 or 3) I normally run 1/2 to 5/8” stick out on it….some people go by cup size and limit stick out that way..
Here’s some of my Furick Jazzy, FUPA, Edge LF, good old ceramic on a 1/16” tungsten…