[gnabgib]

Hi everyone, been a while.
Around a month ago my cylinder of Argon emptied but before that happened I pushed it to the very limit where I copped the ending Co2 contamination.
I got a refill and ran about 60 seconds of gas through but ever since I've had more than any usual porosity which happen sometimes, this though is far too frequent.
This is work I have done before without any real problems. Steel, 2mm wall thickness RHS and SHS pre-gal tubing with galvanizing removed from weld area. 2.4mm Tungsten with a diffuser and size 10 cup, between 74-79 amps. The diffuser is now about 7 years old so I'm wondering if that's the problem as it doesn't look the best. Could it have collected contamination from the gas end? Gas hose? New air leaks?

Jeff

[BugHunter]

Since the gas lens doesn't get hot enough to burn whatever contamination is sitting on it, I would be very skeptical about that being a problem. It's not like having steel gunk on your tungsten where it's at 3000 degrees Fahrenheit. Cleaning the gas lens or replacing it can't hurt but I would almost say it's impossible it causes porosity in a weld.

[Oscar]

..... it doesn't look the best.....

We can't see it from here....

[gnabgib]

..... it doesn't look the best.....

We can't see it from here....

Suppose I meant it seems clogged...
Have you tried squinting? Problem, for such detail I don't think a photo would work.

[gnabgib]

Since the gas lens doesn't get hot enough to burn whatever contamination is sitting on it, I would be very skeptical about that being a problem. It's not like having steel gunk on your tungsten where it's at 3000 degrees Fahrenheit. Cleaning the gas lens or replacing it can't hurt but I would almost say it's impossible it causes porosity in a weld.

Ok. Wondering if residual Co2 and contaminants etc. have collected in the line. Never heard of it before but do know that cylinders and other types gas lines retain deposits.
Anyway I've put the diffuser in boiling water and then washed with Acetone. Something has changed, so to work out what.

[Spartan]

A clogged up diffuser could certainly interfere with the flow of the shielding gas. Definitely worth cleaning or replacing it. I replace my gas lenses every few months or so for this exact reason.

[G-ManBart]

It's possible that when you connected the current bottle and ran for 60 seconds you were really using the gas that was between the flow meter and the gas solenoid, not what was coming out of the tank.

I would definitely start with a fresh everything on the torch, and check for leaks....new collet/collet body/gas lens, etc. If none of that fixes the problem it's pretty likely contaminated gas. If the bottle previously had something else in it and they didn't suck it down properly it will cause issues.

[gnabgib]

It's possible that when you connected the current bottle and ran for 60 seconds you were really using the gas that was between the flow meter and the gas solenoid, not what was coming out of the tank.
What I meant there was, after getting the bad gas at the end of the previous tank I decided with the new tank to run a gas check longer than I usually do. 60 seconds instead of 20.

I would definitely start with a fresh everything on the torch, and check for leaks....new collet/collet body/gas lens, etc. If none of that fixes the problem it's pretty likely contaminated gas. If the bottle previously had something else in it and they didn't suck it down properly it will cause issues.

I've swapped back to a standard torch without a diffuser. One thing that occurred to me though, slow sometimes;-) is that this new lot of welding is now taking place in a room which has an exhaust fan. It moves only 280m3 an hour, minimal and didn't think it would be an issue but it could be creating enough draft to disturb air. That combined with a diffuser which is probably not working effectively.
That and the bottle change over are the only differences from the previous welding work which always went without any real problems.
New gas and bottle swap, is from the same supplier so I don't really suspect that.

[gnabgib]

A clogged up diffuser could certainly interfere with the flow of the shielding gas. Definitely worth cleaning or replacing it. I replace my gas lenses every few months or so for this exact reason.

Thanks. Seems pretty obvious now in hindsight.

[G-ManBart]

New gas and bottle swap, is from the same supplier so I don't really suspect that.

Even the most professional, careful shop can send out a bad bottle by accident....it happens. Guys that run bit operations have even commented that they can figure out a percentage over time that will be bad...they go through X bottles per month and have to return some of them.

My 100% argon bottles are from two different shops. One fills their own, and the second uses the first one to fill their bottles, so they're all coming from the same source which is considered the best place around. I'm good friends with the owner of the second shop and she said that it's pretty common to have contamination when a bottle is changed from one gas to another. I've had bad bottles three times in the past two years or so. Now I test them as soon as I get home and make sure to purge the lines before hooking up the new bottle. I actually had one that was fine on steel but an awful black, sooty mess on aluminum, so it only had a touch of contamination. That's part of why I have multiple bottles...one I'm using that is known good, and a backup that's also known to be good. I got burned one time not testing the backup until I needed it...on a weekend. Luckily, my friend opened her shop and swapped my bottle Sat evening so I could finish up on Sunday.

More often than not, when people describe these problems it only get solved when they swap bottles. In some ways, that's the best outcome...it means your equipment and technique aren't the problem!

[gnabgib]

New gas and bottle swap, is from the same supplier so I don't really suspect that.

Even the most professional, careful shop can send out a bad bottle by accident....it happens. Guys that run bit operations have even commented that they can figure out a percentage over time that will be bad...they go through X bottles per month and have to return some of them.
More often than not, when people describe these problems it only get solved when they swap bottles. In some ways, that's the best outcome...it means your equipment and technique aren't the problem!

Definitely something to consider. Another thing that just occurred to me, is the porosity was happening sometimes a little at the beginning but mostly at the end, in both cases at the edge of the material, a 90deg drop away from the weld plane, so another pointer to gas coverage.

[gnabgib]

After going in circles, it was an air leak, so fixed now, until next time.

[BillE.Dee]

glad you found the problem . The "air leak" was where, so others can look also when they get problems? I'm "assuming" the problem was at the bottle connection since that is the "only" place you made a change?

[G-ManBart]

Definitely something to consider. Another thing that just occurred to me, is the porosity was happening sometimes a little at the beginning but mostly at the end, in both cases at the edge of the material, a 90deg drop away from the weld plane, so another pointer to gas coverage.

Glad you found the problem! Since it wasn't causing problems in the middle of the weld it must have been on the edge with the leak and just not quite enough gas at the ends. Rather than an air leak, could it have just been venting argon out of the leak so you were just getting less gas to the torch than what the flow meter was showing?

I never really thought of it this way before, but most of the time air leaks are probably really argon leaks since the argon is under pressure and it would be hard for anything to overcome that and enter the torch stream.

[Toggatug]

I agree most times I would think it'd be a argon leak.

But my brain says there's a chance depending pressure and type of leak etc that the line could potentially make a Venturi and draw air into the stream.

I figure the moon and stars would have to aligned just right for that to happen though just due to the pressure of the argon versus the atmosphere, but on second thought I don't know a heck of alot about flow and Venturi science I just know the basic principle of what it does.


By all means someone correct me if I'm wrong Or confirm if I'm on the right track cause I'd like to know.

Sent from my Pixel 3a using Tapatalk

[gnabgib]

glad you found the problem . The "air leak" was where, so others can look also when they get problems? I'm "assuming" the problem was at the bottle connection since that is the "only" place you made a change?

Your assumption is correct, not my half-arsed deductions. Seems my cylinder swapping technique wasn't good enough this time. I've done it before using the PTFE thread tape at the regulator to cylinder connection, so took it apart once again, replaced the o-ring and added more tape. Also, removed hose from the gas flow meter, cut the end off it and put on a new hose clamp, including tape on the barb.
Was either at these 2 points or at the torch and even though I spent too much time initially thinking about that, the final give-away were the sparkles in the gas flow at the start and end of each weld.
Got to be thankful that it wasn't something more involved or costly like a new torch, hose or machine service. Or, returning a cylinder of gas.

[Jack Ryan]

I've done it before using the PTFE thread tape at the regulator to cylinder connection, so took it apart once again, replaced the o-ring and added more tape. Also, removed hose from the gas flow meter, cut the end off it and put on a new hose clamp, including tape on the barb.

You shouldn't need tape on either on those connections - if fact, I think you shouldn't use tape on them. If nothing else, you might end up with tape in the regulator.

Jack

[Oscar]

Perhaps the threads on the regulator or the internal threads on the tank valve were compromised somehow, and the teflon tape did indeed help? Tough to say, but so long as it's fixed that's all that matters. I actually had to do something similar with a couple acetylene tanks. They were swaps and had likely seen millions of swaps and the internal seat on the valve was all crudded up so the cone on the "regulator side" didn't seat tightly, and it leaked no matter what I did, no matter how tight I torqued down the fitting. Soap test still showed bubbles no matter what. I ended up using a little tape and it sealed up nicely.

[Jack Ryan]

Perhaps the threads on the regulator or the internal threads on the tank valve were compromised somehow, and the teflon tape did indeed help? Tough to say, but so long as it's fixed that's all that matters. I actually had to do something similar with a couple acetylene tanks. They were swaps and had likely seen millions of swaps and the internal seat on the valve was all crudded up so the cone on the "regulator side" didn't seat tightly, and it leaked no matter what I did, no matter how tight I torqued down the fitting. Soap test still showed bubbles no matter what. I ended up using a little tape and it sealed up nicely.

I guess I'm just overly fussy. I would not have accepted a bottle in that condition as a crudded up seat on the cylinder probably contains inclusions that would do the name thing to the seat on my regulator coupling.

Jack

[gnabgib]

I've done it before using the PTFE thread tape at the regulator to cylinder connection, so took it apart once again, replaced the o-ring and added more tape. Also, removed hose from the gas flow meter, cut the end off it and put on a new hose clamp, including tape on the barb.

You shouldn't need tape on either on those connections - if fact, I think you shouldn't use tape on them. If nothing else, you might end up with tape in the regulator.

Jack

Maybe not but it's out of habit as I do use on other of the usual screw gas connections. Very unlikely it getting into the regulator where even an old o-ring would prevent that

[gnabgib]

Perhaps the threads on the regulator or the internal threads on the tank valve were compromised somehow, and the teflon tape did indeed help? Tough to say, but so long as it's fixed that's all that matters. I actually had to do something similar with a couple acetylene tanks. They were swaps and had likely seen millions of swaps and the internal seat on the valve was all crudded up so the cone on the "regulator side" didn't seat tightly, and it leaked no matter what I did, no matter how tight I torqued down the fitting. Soap test still showed bubbles no matter what. I ended up using a little tape and it sealed up nicely.

The threads on the cylinder and regulator are very good in my case. I might add that in 12 years this is my first problem with an air leak and the lesson once again is to deal with the obvious first.

[gnabgib]

I agree most times I would think it'd be a argon leak.

But my brain says there's a chance depending pressure and type of leak etc that the line could potentially make a Venturi and draw air into the stream.

I figure the moon and stars would have to aligned just right for that to happen though just due to the pressure of the argon versus the atmosphere, but on second thought I don't know a heck of alot about flow and Venturi science I just know the basic principle of what it does.

Sent from my Pixel 3a using Tapatalk

It's possible that it was sucking air in the hose connection at the flow meter and so the cause of the sparkles in the gas at the torch. It was clamped with one of those 2 eared types and the hose did turn on the barb.

[gnabgib]

Definitely something to consider. Another thing that just occurred to me, is the porosity was happening sometimes a little at the beginning but mostly at the end, in both cases at the edge of the material, a 90deg drop away from the weld plane, so another pointer to gas coverage.

Glad you found the problem! Since it wasn't causing problems in the middle of the weld it must have been on the edge with the leak and just not quite enough gas at the ends. Rather than an air leak, could it have just been venting argon out of the leak so you were just getting less gas to the torch than what the flow meter was showing?

I never really thought of it this way before, but most of the time air leaks are probably really argon leaks since the argon is under pressure and it would be hard for anything to overcome that and enter the torch stream.

Thanks. In my case, a mountain out of a molehill. The more I think about it the more I believe it was the hose off the flow meter.
"Did you try turning it off and on?" Hmm ?

[gnabgib]

Porosity problem is back! What I noticed this morning is when doing a 20 second gas test with the flow meter set at my close to usual 7Lpm, as the gas flows it starts rising up to 11Lpm. What? My welder is a Kemppi MasterTig 2300 which has a push-on fitting for the gas hose at the back. Needs the soapy water test there. Just checked a UK site and yes these connectors develop problems.

[kiwi2wheels]

This is the clamp type you need .

https://www.amazon.com/Oetiker-15400039 ... B076G6WWC8