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**MikeR** · 05-17-2003, 12:13 AM

#2

**MikeR** · 05-17-2003, 12:14 AM

#3

**MikeR** · 05-17-2003, 12:15 AM

#3 what the **** happened here?????????

**MikeR** · 05-17-2003, 12:16 AM

#4 proof

**MikeR** · 05-17-2003, 12:18 AM

more proof. I never said I was great!!

**Guest** · 05-17-2003, 12:51 AM

That looks like a gas problem coupled with a tungsten problem...may be too much gas. or not enough. Tungsten may be comtaminated..not sure. When I do an outside corner I turn down the flow rate. Anyway, play with the flow rate, and torch angle...you'll see a difference. Great pictures!

**MikeR** · 05-17-2003, 01:05 AM

Rocky, like I said, I've been from 10cfh to 30cfh and there isn't any difference. I think 10 is alittle low so I settled on 15. Also, I take very good care of my tungsten, and made sure to use a brand spankin' new piece just to be sure. Also, the only thing torch angle seems to change is which piece blows away first!

It seems to be better when I'm 45 deg to the joint and pointed almost vertical in regards to travel, but still the problem persists.

Hope that made sense

**chip hayden** · 05-17-2003, 07:58 AM

heres my suggestions;
1. 003,002,005 look like outgassing. see how it kinda "volcanoed out"? might try a back purge with slightly MORE cfh inside box than outside. also, try using a gas lens[if not already] with a slightly larger cup.
2. to prevent edge melt and smut, as in last picture, stop your weld @ 1 1/2" before edge, then weld from the edge back to the first weld. this won't overheat and boil the verticle. you can go back and remelt the bead if you want it to be symmetrical.

**MikeR** · 05-17-2003, 11:25 AM

Chip, thanks for your reply. I'm willing to try about anything, but have some questions first. Is there an inherent problem with welding thin aluminum like this? I mean, I've never heard of anyone else having to back gas small tanks like this, which leads me to believe that there is another problem that I'm not seeing. I'm a big believer in finding the problem, not finding ways to cover the problem up. Also, the back gas will be expensive... some of these tanks are as big as 4'x5'x1 1/2'. I am by no means discounting your suggestions, just trying to go about this the right way!

I am running a #8 gas lens currently, and am thinking about going back to my regular alumina (?) #7 cup just to see if it makes any difference. I run 15cfh with the gas lens and 20 with the other (stock) type.

Thanks guys! Keep 'em comin'!
Mike

**chip hayden** · 05-17-2003, 12:35 PM

you are right, back purging is costly, and i'm about as cheap as they come, so how about this;
1. i thought solar flux made a shielding paste for aluminum but all i could find was for stainless. aufhauser makes a flux but, i think it's for gas welding aluminum and not really a shielding paste.
2. can you back up the weld with a peice of stainless angle and remove it after welding? this will also give you a good heat sink.
3. i really think it is outgassing. any boxing of the void will heat and expand whatever is in there when you start welding and it will want to burp out.
4. open angled edges tend to split the gas and move it away from the weld zone so that's why i suggested a larger cup. 8 is pretty big though. so i don't think that's it.
5. can you pulse your power supply and/or change the +- time of the welder?

**lranch** · 05-17-2003, 01:33 PM

Hey mike, when you start the tack, does the arc start to melt the parent material right away? When working thin edge stuff I like to sneak up on it. That is: only let the arc dance around a little bit before I begin the tack. During this the parent material should not melt until all the crud has been super heated away. In extreme cases of crud I will bring it up to a shine (just starting to puddle) back off, brush off the brown or black soot, then go again. As a general rule of thumb, I use the same procedure to get going as I use to make the tip. Wait a bit at low non meltin power, material will mess around from dull to almost shinny then back to dull then a uniform puddle will begin to form on both pieces. At this point you can tack or weld. I try and avoid the urge to add a little more power to get going faster as this will result in cheese in most cases. Anyhow, good luck and hang with it.

**MikeR** · 05-17-2003, 03:47 PM

Chip, I came up with the same fluxes you found I think. I also thought about using a copper backer, but that would only solve the problem on big tanks with big openings. small tanks, you couldn't get the backer out after you tack the last end on!! You make a very interesting point about the gas splitting around an outside corner. I've allways wanted to try flowing some kind of smoke through my torch so I could visualize the gas flow and see how much better gas lenses really are, but am concerned with contaminating my liner. Lastly, I'm running a 180SD (about a year or so old) and it is not adjustable at all... frustrating some times but a good machine overall.

Iranch, you also make an excellent point, but unfortunately I tried that, if I understand you correctly. I tried ramping power up until the arc stabilized and keeping it there, however, no matter how low I can keep the power, the material just melts away. As an experiment, I kept dialing amps out until I got down to 30.... that's all it takes to make "cheese". (isn't it funny how many applications that word has??

)

Now that I've said that, I think I may have gotten around the problem.... not solved it, but just bypassed it. I changed my fit-up to more of a lap joint and poof! Perfect tacks and welds. Ok, not perfect, but no contamination..... check it out and let me know your thoughts.

**MikeR** · 05-17-2003, 03:51 PM

**MikeR** · 05-17-2003, 03:52 PM

third.......not much detail, but even this close there's not even any black pepper....

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