Welding Tips and Tricks

Hi all, new to the forum and new to tig. I've been trying to troubleshoot what I think is argon contamination, but I'm also learning. I will apologize in advance. It's been a long road. Here's what I got:
Bought a HTP Invertig 131 in 2014. Didn't really do much with it till recently. Maybe 1 or 2 bottles in 7 years. 3 weeks ago, I did some 1 on 1 instruction with an experienced welder. I brought my torch (ck9 with gas lens, 1/16" ceriated tungsten, #8 cup). The first day was rough. The steel seemed to act dirty, tungstens contaminating quickly, etc. The instructor, after the first day, was using my torch, his welder(Miller Dynasty) and noticed the issue. So he switched back to his torch and the following day I used his torch. Huge difference in weld quality and performance! So I took all my new knowledge and went home to improve on my new skills. Only, I was having same issues again. So I swapped to a new torch body, gas lens, collet and tungsten. Same results. Then I started to find a leak in my argon. Did the whole soapy water and dunked torch and hose(kevlar superflex) in water with line charged. Found a small leak at regulator. Fixed that. Still having the same issues. Tried purging the line with high flow. My questions are: How common is bad gas? Am I missing something? Is it my technique? I was running a higher flow on this weld, but typically run around 10cfh, 50 to 70 amps, and mainly thinner(.8mm to 1.6mm) tubing. All tungstens look like this within seconds. Thank you for your help?

Sorry, smaller image size.

How common is bad gas? Depends on the reputability of the gas supplier really.

Of all the bottles I've gotten for various machines and types of gas etc. I've never had a bad bottle yet so I'm going to say it's unlikely.

But if you have another known good bottle I dont see the harm in swapping over to rule that out.


The blueing on your tungsten just makes me think of heat tinting where the gas doesn't meet the tungsten. My tungsten often gets like that from high amp ally work I don't think it poses any real issue.

I'm not the biggest expert on cup flow settings per joint type but I think 10cfh for a #8 is on the low side. I'd try more in the range of 14-18cfh personally. I usually go double the cup size in cfh as my ballpark then tune if needed, can't remember if that came from a Jody vid or not but it probably did.

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CFH for #8 should be 15-20.
Tungsten shows too short of a post flow setting. Argon is critical during welding to eliminate the atmosphere from the weld area. It is also critical to continue flowing long enough to cool the tungsten and shield the weld from cooling with atmosphere present.

Your Invertig may not have an adjustable post flow, but should run 1 second per 10 amps of welding amperage. If this is too short to get the tungsten cooled, bump the pedal again and run some more gas until the tungsten remains uncontaminated.

You should try to hold the torch still over the end of the weld while post-flowing to shield the area.

bit rusty here but i would check what spacer you have fitted with the gas lens. you may have the wrong one fitted.

Hey, thanks for the replies. This sample weld was in the 20 cfh range. I increased it for this one. The 10 cfh was recommended from the instructor to reduce turbulence and since most joints are tubing, the argon gets trapped a little more (his words). And I have to say using his welder with10 cfh was fine(no backpurge). I'm starting to think it is the gas lens. Based on the CK diagram for their #9, I'm pretty sure I have the right insulator, which is the same for a standard collet or a gas lens. Gas lens purchased from a welding supplier. Not sure on the actual brand, I can check with them. Just inscribed 1.6 1/16. I've swaped out gas lens's twice in the last month, all from the same supplier. Are there that big of differences in gas lens for a ck9 torch? Did some more welding yesterday. Same results. More sizzling and bacon frying.

Just think I should mention. If your instructor was running a collet body his gas flow rates will be different than your gas lense requirements.

If you have a collet body style piece I'd install that and rule out whether or not the gas lense itself is posing the issues.


Also worth asking of the backside of your tubing has been cleaned and if a backpurge is done while welding as both of those things can also play a role in contaminated welds.

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Tubing is thoroughly cleaned inside and out, deburred. I tried a new tank of argon today. Same results. Bluing of the tungsten inside the cup. Black around the weld. Starting to think it's the gas lense, again. Maybe restricting the gas somehow.

Boedie wrote: ↑Tue Nov 30, 2021 8:18 am Are there that big of differences in gas lens for a ck9 torch?

yeah huge. seen a few get stung with no name gas lens that don't work.
pay the extra and stick with well known brands. (support jody https://weldmongerstore.com/ )
CK are good, but there is others. for the amount of lens you go through its not worth buying cheap.

I do have some new gas lens's coming from weldmonger, only for a 17 series torch.....because I have a new Lincoln Tic welder arriving tomorrow. I wanted to weld ac as well, and this seemed like a good opportunity to upgrade. Still have to troubleshoot this welder before I sell it. Hoping it is the gas lens. Thanks for the suggestions!

Yes, budget/import lenses simply suck, maybe not always, but sometimes they do exactly what you're seeing there, and I'm speaking from person experience, I'd first suspect a poor quality gas lens, if that doesn't fix the issue, You may try snugging all the fittings on your hose on regulator up a good bit, but be careful not to overtighten. You can put some force into tightening the regulator onto the bottle itself, in my experience with some bottles that have been severely overtightened before, or if your regulator has been overtightened, it'll take a bit more force to get a good seal than it would with fresh new threads on the regulator and cylinder first, the smaller fittings DON'T take much force though, snug, but not tight.

Also aim for around 7/16-9/16 stickout with a number 8 cup and gas lens and run 20CFH, that's generally the sweet spot and you can deviate away from that some, at 10CFH you're almost guaranteed to have very very poor shielding, while 30CFH especially with a shorter or longer than normal stickout will really start to show the effects of turbulence.

I would try a regular (non gas lens) collet body/cup with only 3/16" stickout using a 3/32" ceriated tungsten (if that is the only tungsten you have). 2 to 3x the diameter for the gas flow.

You don’t have a contaminated tank. Your welds are fine, just heat soaked. Your tungsten shows a lack of sealing by the insulator (cheap lens). Collet bodies use 1-1.5x as a flow rate to cup size. A #5 collet body cup only needs maximum of 8CFH.