[StephanusThie]

Hi all,
Tried the bumping tech yesterday, the material is a broken car velg, anodized like a mirror, thickness about 5-6mm. I used Syncrowave 250DX, the settings are: 8LPM 100% Argon, 3/32 1,5% Lant tung, gas lens with cup #6, WP18, 150Amps, balance at 4 (balanced?), wiped with thinner (got no acetone here). I can get a puddle in about 2-3secs, it's a clean puddle.
The problem is when I dab the filler (4043) for the second time. The puddle will soon contaminated (looks skinny). No problem when first time dab. The cleaning area not seen.
The question is what did I do wrong? Is it normal not to have a cleaning area when bumping the anodized? Maybe the cup was to small?
Any information and suggestion is greatly appreciated. Thank you all in advance.

[Otto Nobedder]

It does sound like insufficient gas coverage... when pulling the rod from the puddle on the first dab, it may be seeing enough air to oxidize, giving you that "skin" on the second dab. Enough heat may be travelling up the rod to oxidize it outside the coverage area.

I've never welded anodized without grinding the finish back from the weld zone a bit, so I can't speak to the absense of a "cleaning zone", but I can speculate that with the hardness, thickness, and high melting point of the finish your "cleaned zone" would be a fine line at the edge of the bead and not be obvious as on bare aluminum.

Steve S

[StephanusThie]

Hi Steve, thank you for your time.

So I think maybe I need a bigger cup? and higher flow? What do you think about the amps?

[Otto Nobedder]

If you're getting a puddle in just a few seconds, your amps are fine for the material; I've had it take ten seconds on heavy sections to get a good enough puddle to start welding.

A #6 is a small cup for Al, but I do it with a #8 often (I'll use bigger if it's available).

8 LPM is about 16-17 CFH, if my math is right, and I normally use twice that (around 35 CFH)

Steve S.

[Otto Nobedder]

Yep...

Did the math both directions using the assumption 4L = 1Gallon (It doesn't, but it's close enough for estimating gas flow).

The 35 CFH I use translates to about 16 LPM.

And, yes, a larger cup always helps with higher gas flows, as there is less turbulence.

Steve S

[ajlskater1]

Usually on Ana al the costumers do not want to see a cleaning area around the weld. At my previous job I did do some Ana al, we used a millet dynasty 700 and it had wave shape called triangle designed for welding Ana al, it helps punch through the anadizing without leaving the etching outside the weld. I have done some at home as well using a dynasty 300, it doesn't have that feature so I just manually pulsed the foot pedal and it worked good. I would say 35 is crazy high for al. At work I normally run around 20 cfh for outside corner joints and number 8 decider. On butt welds or t joints I run about 10 to 15 cfh same cup. You do not need to run a lot of argon on al like you do stainless or titanium.

[Otto Nobedder]

My welds sometimes fall under an ASME WPS. I do what the WPS says do.

I don't buy my gas. We buy argon and nitrogen from our clients, and sell back what we use at %30 markup. One client Gives us helium in quantities we are forced to waste.

35 CFH through a gas lens makes a reliable weld even in light wind.

I suppose it's excessive in calm air.

[ajlskater1]

Ya I have only welded in shop environment with no air movement thats probly why we ran lower cfh but everything passed xray. I just dont get how you weld a t joint a 35 cfh I have messed with that at my home shop and the arc is so irratic and the bead looks chauky

[Otto Nobedder]

Just caught what you said about Tee joints.

I usually weld round things (small tube and pipe, large vessels, and such).

I do crank the gas back if I'm filling a corner. Open surfaces get lots of gas.

[ajlskater1]

Hmm even on tube I would run like 20 with number 8 cup. But than again it was in inside a shop on a turn table or manually inside. I might have to pull the welder outside and try running higher gas. What size cup do you run when running that high of gas flow?

[TamJeff]

Our shop is in FL. It gets over 100 in the shop so I have fans 'on' me at all times and I mostly weld anodized. Even then, I run 15-20 cfh. I typically run 20, #7 cup with no lens, 1/8" pure tungsten and 1/8" 5356 filler. 15 if I think to turn it down to save gas and I usually don't have shielding issues, even outdoors. If you think it's a gas issue, try welding reverse travel so that the gas is definitely directly on the puddle. This works with two different machines. A Dynasty without high freq and a syncrowave with continuous high freq. Both machines welds look identical.