Gas flow with gas lens.

[Bladevane]

As I’m only a beginner I have tried to reduce the number of variables and one of them is gas flow. I have stuck to 8 lpm. However last night as my gas bottle was nearing end of life the flow was reducing but I continued welding really to see at what point low flow became a problem. To my inexperienced eye gas flow as low as 4 lpm did not seem to affect the weld. So I looked up an article on the Miller site which confirmed a benefit of using a gas lens is reduced flow from between 1.5 - 2.5 lpm.

What is your experience?

 

[Brad93]

As I’m only a beginner I have tried to reduce the number of variables and one of them is gas flow. I have stuck to 8 lpm. However last night as my gas bottle was nearing end of life the flow was reducing but I continued welding really to see at what point low flow became a problem. To my inexperienced eye gas flow as low as 4 lpm did not seem to affect the weld. So I looked up an article on the Miller site which confirmed a benefit of using a gas lens is reduced flow from between 1.5 - 2.5 lpm.

What is your experience?

No way. I’d say your gauge is faulty. Below 3-4lpm you can see welds going bad.

Have you had a pea shooter at the torch end to check the flow?

 

[Bladevane]

Let me rephrase the question to make it clearer.

Does anyone have experience of being able to reduce argon flow when using a gas lens?

 

[eSCHEn]

Yes. I went from standard collet body to a gas lens a wee while after starting. I was running ~7 - 8 lpm on the standard body and once onto the gas lens I dropped to about 5 - 6 lpm.

When you're doing dirty welds such as galv you want to go back to the standard body as the crap that spits off can ruin the lens.

Flow rates were done using a flowmeter after the regulator.

 

[Brad93]

It’s all circumstantial because we don’t know what size ceramic you’re using, what style of gas lense, or what your gas set up is.

I’ve never run 7-8lpm through a collet body. There’s no need, 6lpm is fine up to a #7 ceramic.

Can you run less gas with a gas lens?
Yes you can, you get a smoother more laminar flow of gas exiting the cup. This means that the shielding should be about equivalent even though using less gas.

Should you use less gas?
Well unless you’re going to start carrying out macroscopic and microscopic etches of your welds you’re never going to know.
Nitrogen embrittlement is the largest factor with welds in steel that will be encountered with insufficient gas flow.

If I put on a gas lens with a #6 ceramic, I leave my flow at 6lpm, if I go to a #8 I might bump it to 7lpm, #10 I’ll go to about 8/9lpm.

I never go below 5lpm with a collet body.

The smallest ceramic I own is a #4.

 

[Richard.]

While gas lenses claim to allow you to reduce flow that’s not really the biggest advantage from one and certainly not the reason I use them for 99% of what I do.
A gas lens provides a quality shield. The gas exits the lens in a straight down fashion through a series of gauges to smooth out the delivery. This can aid to reduce your flow (cup for cup) but for me it’s not about that. It’s about the quality of the delivery and the positive effects on strikes and weld quality.
Collet bodies are fine and in general you can hit similar flow rates with a body as you can a lens and have no problems. They don’t provide a quality shield like a lens particularly on gas cooled set ups where the cup is smoking hot and the gas is made to deflect off the hot cup walls. I notice the difference more in striking. The accuracy of the hf from my experience is better with a lens with how the argon flow carries the hf. It’s not bad with a collet body but you can notice the difference particularly if your doing lots of tacking up.
As Brad said cup size is most important. You wouldn’t have much fun pushing 8 Lpm through a number 4/5 cup in the same respect you wouldn’t if you whithered it out of a no 12.
I am a no 7 cup man myself and 5,6 lpm joint depending is where I usually stay. That wouldn’t change much if it was a collet body or a lens.
You don’t need a lens. They are not essential unless you start getting into exotics. I use them because I like them but could get on fine on the most part with collet bodies if I needed to.

 

[Appyasme1]

As I’m only a beginner I have tried to reduce the number of variables and one of them is gas flow. I have stuck to 8 lpm. However last night as my gas bottle was nearing end of life the flow was reducing but I continued welding really to see at what point low flow became a problem. To my inexperienced eye gas flow as low as 4 lpm did not seem to affect the weld. So I looked up an article on the Miller site which confirmed a benefit of using a gas lens is reduced flow from between 1.5 - 2.5 lpm.

What is your experience?

You mention that the gas flow changed when the gas bottle was nearly empty,are you using a single stage regulator?If so the pressure would change as the bottle empties. Any thoughts guys?

 

[D5meister]

One disadvantage of a lens is the torch runs hotter from the reduced cooling (from less gas flow)

 

[Jlg]

One disadvantage of a lens is the torch runs hotter from the reduced cooling (from less gas flow)

Not water cooled

 

[Richard.]

One disadvantage of a lens is the torch runs hotter from the reduced cooling (from less gas flow)

The difference in flow rate if any is so small I don’t think the torch would notice much in temp at all.

 

[Richard.]

Lens main disadvantages are
1) price. At least 3-4 times more than equivalent quality bodies
2) size. A lens will always be a tad more cumbersome than a collet body.

 

[zeppelin builder]

One disadvantage of a lens is the torch runs hotter from the reduced cooling (from less gas flow)

Big gas lens with big lpm actually cools the torch ,its like a big gas cooled heat sink

 

[AndersK]

If this link works it shows difference in gas flow using std body vs gas lens

https://www.instagram.com/p/Bm9cKxuAtnW/?utm_source=ig_share_sheet&igshid=1xyai4wk6lq2n

 

[mrsbruce]

If this link works it shows difference in gas flow using std body vs gas lens

https://www.instagram.com/p/Bm9cKxuAtnW/?utm_source=ig_share_sheet&igshid=1xyai4wk6lq2n

Unfortunately, my ipad did not like that link.

 

[zeppelin builder]

If this link works it shows difference in gas flow using std body vs gas lens

https://www.instagram.com/p/Bm9cKxuAtnW/?utm_source=ig_share_sheet&igshid=1xyai4wk6lq2n

Been more realistic if held at the proper distance and on different joint confiurations
e.g. outside corners

 

[Appyasme1]

Lens main disadvantages are
1) price. At least 3-4 times more than equivalent quality bodies
2) size. A lens will always be a tad more cumbersome than a collet body.

Regarding price. If you do want to go down the gas lens route make sure you buy a quality lens such as CK.There are loads of 2nd class gas lenses out there.Buy cheap pay twice!