Need help/arc welding aluminum? Welding experts!

[Reumster]

Ok I know that arc/stick welding aluminum isn't the best way. But it's what I have to work with. My question to the welding experts is whats the best way to set the welder up? I'm using a older Lincoln welder. What setting should I start with. DC-/DC+ or AC, what dial settings? I tried welding a couple beads, but it was pretty ugly! LOL the weld seems to want to clump up, or bead really tall. I'm a really good stick welder on steel but aluminum is hard. Also is there a aluminum rod anyone recomends? I'm going to try to make my own custom aluminum air tanks. If I can get this welding down.

[Fred T]

Stick welding of aluminum is not recommended. My book on welding aluminum doesn't even mention it as an option. If you are welding aluminum air tanks with a stick, you are inviting disaster. Stick welding aluminum will create cracks, voids, stress risers and stress corrosion. Welding pressure vessels should be done only with GMAW or GTAW. Aluminum can also be welded with oxy-acetylene, but I couldn't recommend it for pressure vessels since you don't have an inert gas shield.

Sorry to be so hard on you, but I think you're headed down a path you don't want to follow.

[Southpa]

Howdy Reumster, most aluminum welding is done w/ AC or DCEP (Direct Current Electrode Positive= Reverse Polarity). DCEP(RP) can be successfully used for thicknesses up to 3/32". Gas shielded welding is desirable to protect the aluminum from oxidation but flux coated aluminum electrodes are available. You might have to match the aluminum content in your electrodes with that of the base metal you are welding on.

You have a choice of 3 electrodes designated in the AWS (American Welding Society) A5.3-80 booklet on non-ferrous electrodes.
E1100 = aluminum content of 99%
E3003 = aluminum content about 96.7%
E4043 = aluminum content about 92.3%

You won't find much info on stick welding aluminum, basically because its not normally practiced. But I guess regular gas welding specs would apply.

1/16" thick. - 1/16" rod - 60- 90 amps AC
1/8" thick. - 3/32 or 1/8" rod - 125 to 160 amps AC
3/16" thick. 1/8" rod - 190-240 amps AC
1/4" thick. - 1/8 or 3/16" rod - 260-320 amps AC
3/8" thick - 3/16 or 1/4" rod - 330-380 amps AC

I know the amperage covers a broad range but the currents work for butt, lap, corner and fillet welds in ascending order of amperage. Also you will be looking at multiple passes for thicker base metal. Aluminum welding is always done hot and fast.

I have to agree w/ Fred on the matter of pressure vessels. If you are attempting to make scuba or air compressor tanks, they should be TIG welded by a pro. These tanks are capable of holding enormous pressures. Even striking an arc on the exposed surface of any pressure vessel in a repair attempt will make it unstable and unreliable.

[Gee_Emm]

I didnt even know that you could stick weld aluminum. I have done mig welding with aluminum and to get a decent weld your two metals have to be sqeaky clean.

[bigjimzlll]

what ever happened to heli-arc welding for aluminum..

[Mike C]

Are there any further concerns with gasses and vapors when weldeing aluminum? Just curious if you should wear respirator of some sort.

[Reumster]

I was afraid of all that. I knew that I was most likely to take the tanks to a place with a tig welder. I tig welded aluminum in the Navy but I don't have access to one. The guy I asked for a price quote said 45.00 a tank. I'm making 4 aluminum tanks for my air bag set-up. I guess I could try radiator repair shops they generally have tig welders.