[AnonymousWelder]

Having a bit of a head-scratcher and I need some help.

Working with 2 different gas lens setups, doing a lap weld on 1/8" mild steel coupons with 1/16 filler, 1/16 tungsten, and about 130 amps:

[*]CK 17 series torch
[*]CK 4 series stubby gas lens (#4GL116) with a #8 screw-on cup. About 1/2" of stickout.
[*]CK 3 series large diamater #18 pyrex. About 1" of stickout.

I just can't get shiny/colored welds out of the #8 cup no matter what I do, even doing really small beads that are within the cup the entire time. I've tried 25cfh, 15cfh, and 8cfh. All give pretty much the same result although the puddle dances around a fair bit more at 25cfh than 8cfh.

I switch over to the #18 cup at 25cfh and get beautiful beads with exactly-as-expected straw-to-blue color depending on the temperature.

Am I doing something wrong? Are stubby gas lenses just not as good as short or regular gas lenses in shielding? Am I still getting solid welds but it's just cosmetic?

(some of these #18 welds are more "stacked" then I would like...my tungsten was a bit contaminated and I didn't want to regrind it)

[cj737]

It’s nearly impossible to diagnose, but a few things to review are:
Is the lens/torch assembled correctly?
2x cup diameter is the target for CFH. Perhaps a tad less. Too high and you create turbulence.
I’d use a 3/32 tungsten for 130 amps
Insure that all 3 sides (included edges of both pieces) are chemically clean, filler too.
The coloration is a result of heat accumulation. Shiny silver welds on mild steel is not overly common. And it’s unimportant. Penetration matters more than appearance.

And check the angle of your torch with a lap weld. Point directly at the root and keep the bead below the top edge. Splitting the top edge causes a disruption of the shielding gas and can introduce oxidation.

Hope that helps-

[AnonymousWelder]

It’s nearly impossible to diagnose, but a few things to review are:
Is the lens/torch assembled correctly?
2x cup diameter is the target for CFH. Perhaps a tad less. Too high and you create turbulence.
I’d use a 3/32 tungsten for 130 amps
Insure that all 3 sides (included edges of both pieces) are chemically clean, filler too.
The coloration is a result of heat accumulation. Shiny silver welds on mild steel is not overly common. And it’s unimportant. Penetration matters more than appearance.

And check the angle of your torch with a lap weld. Point directly at the root and keep the bead below the top edge. Splitting the top edge causes a disruption of the shielding gas and can introduce oxidation.

Hope that helps-

Thanks you for the reply. As far as I can tell I'm assembling the torch right. The gas lens was brand new, 99% sure that I'm using the right insulator. Everything else about the torch like the back cap, what is being welded on, the filler, the tungsten, etc was identical.

Seems like with the #18 I can't put down a bad looking bead. Last night I was running bead after bead on top of each other and they all look shiny and great (until the entire piece got so hot that even 16 seconds of postflow the bead "converts" purple when the gas goes off).

I've ordered CK's "short" gas lens which uses o-rings instead of screw-on style and has a bit more room to allow the gas flow to develop than the stubby style. I'm just really curious if it'll help or if I need to be using a giant cup if I want super clean looking welds (even on mild steel)

[Oscar]

Don't waste argon. Create/invent clever ways to use a active heat-wicking for the actual part. It works wonders.

[Spartan]

Try increasing your travel speed (try for double), and also try a 3/32" filler rod. The larger rod helps to pull a little extra heat out with each dab. Also try bumping the amps up a bit. I'd have 140 or so at the pedal, start off hot and fast, and then back down to the 120-130A range as things get moving.

[tweake]

Having a bit of a head-scratcher and I need some help.

Working with 2 different gas lens setups, doing a lap weld on 1/8" mild steel coupons

is that mild steel or stainless ?
the pic looks more like stainless.

the other issue is keeping the rod in the gas flow, which a bit harder to do with smaller cups.

[AnonymousWelder]

Having a bit of a head-scratcher and I need some help.

Working with 2 different gas lens setups, doing a lap weld on 1/8" mild steel coupons

is that mild steel or stainless ?
the pic looks more like stainless.

the other issue is keeping the rod in the gas flow, which a bit harder to do with smaller cups.

Mild steel coupons.

Try increasing your travel speed (try for double), and also try a 3/32" filler rod. The larger rod helps to pull a little extra heat out with each dab. Also try bumping the amps up a bit. I'd have 140 or so at the pedal, start off hot and fast, and then back down to the 120-130A range as things get moving.

My pedal is set for about 130-140 which is where I start at and then back off a touch when the lap edges fuse and the puddle gets going. I would try 3/32" filler but I don't have any in ER70, only 1/16"....I've only previously welded stainless so 308/309 is the only stuff I have in 045, 1/16, and 3/32. On the todo list to buy some

['Stang]

Ok! It's a simple lap joint. There is no need for that excessive stick out. Try going to 1/8 stick out with 18 - 20 cfh. You are getting your cup too far away from the joint for good gas coverage. I would also go to 3/32" tungsten. That is my go to size. Hope this helps! This is based on the #8 stubby gas lense.

[sbaker56]

Looks to me like you're starting to melt through on the 8 cup beads while with the 18 they almost look a little cold for my tastes. I hate running beads on thinner material for this exact reason, the plate heats up and warps very quickly and the line between hot enough and melting through can become razor thin. I can tell you from experience that welds that start to melt through or are simply welded with too much heat almost always have the same dull gray appearance.

Also your stick out is fine in my opinion though If I'm running the full diameter of the cup, I like to go an minimum of 2x times the cup size in CFH and prefer more like 2.5x in some situations. When your cup blocks your view of your tungsten and puddle or you have to adopt an uncomfortable position to see your tip to work distance and travel speed can become horribly inconsistent.

[AnonymousWelder]

Also your stick out is fine in my opinion though If I'm running the full diameter of the cup, I like to go an minimum of 2x times the cup size in CFH and prefer more like 2.5x in some situations. When your cup blocks your view of your tungsten and puddle or you have to adopt an uncomfortable position to see your tip to work distance and travel speed can become horribly inconsistent.

I've also found that about 25 seems like good flow with the #18 even running 1" stickout; still perfectly shiny / colored beads. I could probably drop it back to 20 or so when I don't need that much stickout but I was working in some tight areas. I'd say 10 is a reasonable number with the #8 cup since it didn't seem to change vs. 15 or 25 but I haven't gotten a really awesome looking weld yet

I have no idea how anyone could see what they're doing with 1/8" stickout on a #8 cup. That's either going to require way too much torch angle to peek under it or having your head on the table where then you can't see where the tungsten is going. Even at 1/4" I'm struggling to see what I'm doing while keeping the torch close enough to vertical so I'm not flame-throwing and melting the filler outside the puddle (the 1/16" filler isn't helping here either).

['Stang]

It's pretty simple. You keep a slight torch angle and weld toward you. With a slight tilt to the torch, and I emphasize slight, you can see the tungsten fine. You only need the long stick out on constricted areas. Your stick outs on a lap joint are excessive and are compromising you gas shielding. Hope this helps.

[sbaker56]

I did some welding on 1/8 with a 8 gas lens today, and I'm still inclined to suspect the issue to be a combination of you for whatever reason or another being hotter and starting to melt through on your passes with the #8 and never going outside the range of shielding your huge 16 cup offers. However you should regardless have a bright and unoxidized spot at the end of each weld where your post flow will continue to shield even if you were using a standard collet and #6 cup you should get that, the fact you don't means you're losing shielding for whatever reason before the metal cools. Perhaps you're overheating the metal by traveling too slow, or using more of a stick out than you think, because a #8 cup using 1/2 an inch stick out at 20-25CFH is quite fine. I dislike running beads on 1/8 for this reason, even the reduced table contact caused by a slight warp to the plate is going to drastically change your bead appearance using the same settings and travel speed.