ARC Welding Aluminum

[KenWittlief]

Straight arc welding, with a stick welder, Im pretty sure the answer is no. You can weld steel with it, you can even braze with it

but when you get aluminum hot enough to melt it combines with the oxygen in the air and turns to a white powder / dust.

Aluminum is normally welded with a MIG welder using an inhert gas. This is a type of arc welder that feeds wire from the center of a handle. It is also connected to a cylinder of argon or carbon dioxide. As you weld the gas flows out over the weld in progress, keeping it in an envelope of the inhert gas. Since no oxygen is present, the alum does not oxidize into dust.

Its also great for welding steel and stainless steel, because you do not need flux wire or flux core welding sticks (which cover the weld with a crusty ceramic like covering to keep it from oxidizing while it cools)

someone correct me if Im wrong on this - technology keeps changing so fast - but Im pretty sure you need a gas envelope MIG wire welder to weld aluminum

But even if it is a plain old stick arc welder, Im sure you will find many uses for it for your team. If steel is too heavy for most of your robot components and chassis, you could still use it for making a robot cart, special tools, or small metal parts on the robot.

[Gabe]

Yes you can, but I have never heard of it being recommended. Aluminum arc welding rods can be bought, but are only meant for a welder that has a direct current output or has direct current capability. It is easy to know if your welder is the right one because it will be labeled so. As for buying rods, you can buy them from welding supply stores, but the easiest is to buy it from McMaster-Carr. Their website is here: http://www.mcmaster.com/
Search their site looking for arc welding electrodes. The specific electrode you are looking for is specialty electrode E4043. The E means it is a electrode and the 4043 is the number for that specific aluminum alloy. It will be $15 for a half pound of welding rods, and there are 35 to 50 rods per pound.

However, I must add that since you have never used an arc welder before, learning to weld using aluminum rods might end up being very discouraging. Practice with steel first and steel welding rods to get the feel of it, then try aluminum. And always, tell us how it goes!

[KenWittlief]

ok, Gabe is right. You can buy alum rods for a stick welder

but.... like he said, they seem to be used only when you have no other choice.

I googled this website up, they seem to know what the deal is:

http://www.weldingweb.com/showthread.php?t=2641

[sanddrag]

Originally Posted by KenWittlief

Aluminum is normally welded with a MIG welder using an inhert gas. This is a type of arc welder that feeds wire from the center of a handle. It is also connected to a cylinder of argon or carbon dioxide. As you weld the gas flows out over the weld in progress, keeping it in an envelope of the inhert gas. Since no oxygen is present, the alum does not oxidize into dust.

I believe the preferred method of welding aluminum is with a TIG welder, unless it is a high volume production shop or really long beads. The problem with MIG welding aluminum is feeding the wire. It is very soft and tends to bunch up. If you keep the gun hose totally straight, it may work. When MIG welding aluminum, a spoolgun is the weapon of choice. This puts the wire right on the gun so it has a very short distance to feed. Unfortunately spoolguns are usually many hundreds of dollars.

Aluminum is usually welded with 100% Argon shielding gas.

The nice thing about stick welders is that you get the most power for your dollar, and you don't need to worry about wire speed and shielding gas and that sort of thing. You will have to chip off slag though. It is possible to make some really nice welds using a stick welder, but it takes practice. Vertical and overhead welding is definitely much easier with a MIG.

For stick (arc) welding aluminum, I know they make the rods, but I haven't heard any stories from anyone who's used them. If you try it out, be sure to let us know!

[woodman]

Tig is best choice-has the best penetration. Mig will work great. We used migs on production line with no problem welding aluminum doors for RV's. Migs have less penetration than tig. Arc can be done, but its tricky. Welded up some guards for some saws without much trouble. I have had better luck welding heavy wall aluminum tube with aluminum stick. Those guards were .125 sheet, and used 5/32 rod and it worked OK. I work in the maintenance field and do some welding almost every day. In my job I have used all 3 methods of welding aluminum. If you can, tig it.
Dennis

[sanddrag]

Originally Posted by woodman

Mig will work great. We used migs on production line with no problem welding aluminum doors for RV's.

Were you using a spool gun? If not, did you make any changes to allow you to feed the aluminum wire?

[woodman]

We used a couple of spool guns in the main weld shop. In the door assembly area we had 4 welders that was "right out of the box". All standard equipment. One of these welders we would change over when needed (aluminum-mild steel) by changing wire and gas. We used same guns and whips.

Originally Posted by sanddrag

Were you using a spool gun? If not, did you make any changes to allow you to feed the aluminum wire?