Aluminum.

[aczeller]

okay. i've heard alot at work about how much of a PITA it is to weld Aluminum. we had a couple welders try to test on it today... i'm not sure how they did. anyway, why is aluminum so bad to weld? does it require less heat? more control? what is it? no one at work was willing to give me the time of day since i'm the new guy that sits behind a desk all day (i'm a draftsman, not a welder, but i want to learn welding in the worst way). from what i understand about aluminum, it is a less-dense metal than steel, thus making it lighter, and it dissipates heat at a much faster rate than steel. i am curious to know if it is possible to do it with my Lincoln 100HD? i know i'd have to get new wire and probably some gas, but what all does it take?

sorry for being so dim-witted about it, but i'm just curious.

thanks!
Andy

[Engloid]

When I was teaching welding, I had more students pick up aluminum quickly than I did stainless. Aluminum isn't nearly as sensitive to heat, and can be easier to learn. It's just different.

[aczeller]

Originally Posted by Engloid

When I was teaching welding, I had more students pick up aluminum quickly than I did stainless.

ha... that's weird. about 90-95% of the stuff we weld at work is stuff that me and my engineering budies specify as 304/304L or 316/316L SS. i woudl think that they woudl be able to get it fairly quick then. oh well... maybe they are all just a bunch of pansies. after all, most of them like Iowa State ... hehehehehe

later,
Andy

[hotrodder]

aluminium's not difficult, just very different to steel

no colour change as it heats up to melting temp takes a bit of getting used to

the naturally occuring oxide film melts at about 3 times the temp of the aluminium- this can cause problems if the Al isn't clean enough / welder settings wrong

because Al is such a good conductor of heat, more amps are required to get a puddle going. however it has a low melting temp so it's very easy to get into problems until used to its characteristics

your 100HD isn't powerful enough

[proweld]

cleaning the alum. is VERY important. if your machine doesnt have the amps to do a particular job, you can try pre-heating with a torch or some other way of heating, then it will take less amps to form the puddle.
use a pure (green tip) tungsten, AC for tig, use DC reverse to ball the tip of the tungsten before you start (just start an arc on dc+ for a second or two)

just experiment, good luck

[Rojodiablo]

Andy, you can search "aluminum mig welding" and you'll see some threads we have posted on this subject. But basically, yes, you can weld aluminum with your Lincoln 100. It is not easy, and you will need some serious patience. Lincoln has a new spoolgun you could get to make it much easier to do. I would personally say for mig welding as a hobby, at least find a spoolgun to do it with. Maybe even adapt the new Miller spoolgun to fit your welder. The new Miller gun is $200; a good value. You could switch it to a larger machine, like a 175A machine, and you will get better results. Aluminum needs more amps typically, as the heat does dissipate faster. Say I were welding steel, or SS, 1/4" thick: (TIG) I could get an arc formed with maybe 30amps, and then add more until I got the correct size puddle to start adding my filler. There would be basically no "Penalty" for lower heat, just not the penetration needed. But, with aluminum??? If I were to try that, I would not be able to hold an arc well. And, since the puddle would not form well, I would wait around until that magical moment when the aluminum turned to mush, and the whole thing drooled away. So, to start a weld on aluminum of 1/4", I would mash the pedal to the floor, with the amps at 175-225, and get a puddle formed very quickly. Then, I would regulate my heat with the pedal, and add filler quickly. For MIG?? The heat will have to be at max. The wire speed will have to be about 7-8 for that machine.And as for thickness, your machine will weld about 1/8"- 3/16 on multi pass, or with preheat. I used to do it a lot. It's a pain in the rear. My 175A mig is about 10 times better at it- no lie. So much better flow on the aluminum. The little machine will leave your welds humped up a bit, as the arc will not be wide enough to get a smooth flow out on the weld bead. I wish you luck. And, more importantly, access to a tig machine!!! Good luck, Paul.

[proweld]

oops! I didnt see that he wanted to mig weld alum.

[Go1lum]

Proweld balled pure tungsten is old school. Just get some thoriated or cieriated sharpen it to a point and you'll be good in the hood.

[weldgault]

In MIG welding Aluminum Reverse Polarity, (electdrode Positive) is correct. 3/64 or .045 is the most popular size. A spool gun is the best for what you have, but I have seen people use a regular mig gun of about 10' long, kept very streight. Alum is like a chain, it is soft and hard to push. DCEP gets into Electrons and protons, Oxides on the Alum, melting temperature. Tig is a different story, if you want that. John

[proweld]

Go1lum, I was just trying to teach him some basics. I have actually found that zirconated or named something like that, can really hold up to very high amps.

oh, and i wasnt calling him pumpkin. it was supposed to be a smiley face pumpkin at the end of my first post.

[weldgault]

Reverse Polarity in the AC cycle for Tig or DC for Mig
aluminum is what cleanes the oxides off the aluminum, but It should be as clean as possible to begin with.

[proweld]

Originally Posted by weldgault

Reverse Polarity in the AC cycle for Tig or DC for Mig
aluminum is what cleanes the oxides off the aluminum, but It should be as clean as possible to begin with.

huh?

[hotrodder]

Originally Posted by weldgault

Reverse Polarity in the AC cycle for Tig or DC for Mig
aluminum is what cleanes the oxides off the aluminum, but It should be as clean as possible to begin with.

Proweld, weldgaults saying (or trying to ) that DCEP breaks up the aluminium oxide layer (electron flow is from -ve to +ve. when the work is -ve (DCEP) electrons leaving the work remove the oxide layer)

with TIG AC polarity is constantly changing and for MIG it's DCEP



everyone, Andys got a little 100amp MIG set. no point in talking about about tungstens!

while theoretically it'll weld Al, in practice the machine isn't powerful enough to weld anything useful- i'd guess 1/8" would be pushing things and thin Al with a MIG isn't fun

it's simply not worth going to the expense of wire, gas etc to try

[proweld]

Originally Posted by hotrodder

Proweld, weldgaults saying (or trying to ) that DCEP breaks up the aluminium oxide layer (electron flow is from -ve to +ve. when the work is -ve (DCEP) electrons leaving the work remove the oxide layer)

with TIG AC polarity is constantly changing and for MIG it's DCEP



everyone, Andys got a little 100amp MIG set. no point in talking about about tungstens!

while theoretically it'll weld Al, in practice the machine isn't powerful enough to weld anything useful- i'd guess 1/8" would be pushing things and thin Al with a MIG isn't fun

it's simply not worth going to the expense of wire, gas etc to try

I understand all this. I was just trying to figure out if he was for real.

[aczeller]

thanks for all the info. i really appreciate it all.

Later,
Andy

[tanglediver]

Originally Posted by Rojodiablo

Andy, you can search "aluminum mig welding" and you'll see some threads we have posted on this subject. But basically, yes, you can weld aluminum with your Lincoln 100. It is not easy, and you will need some serious patience. Lincoln has a new spoolgun you could get to make it much easier to do. I would personally say for mig welding as a hobby, at least find a spoolgun to do it with. Maybe even adapt the new Miller spoolgun to fit your welder. The new Miller gun is $200; a good value. You could switch it to a larger machine, like a 175A machine, and you will get better results. Aluminum needs more amps typically, as the heat does dissipate faster. Say I were welding steel, or SS, 1/4" thick: (TIG) I could get an arc formed with maybe 30amps, and then add more until I got the correct size puddle to start adding my filler. There would be basically no "Penalty" for lower heat, just not the penetration needed. But, with aluminum??? If I were to try that, I would not be able to hold an arc well. And, since the puddle would not form well, I would wait around until that magical moment when the aluminum turned to mush, and the whole thing drooled away. So, to start a weld on aluminum of 1/4", I would mash the pedal to the floor, with the amps at 175-225, and get a puddle formed very quickly. Then, I would regulate my heat with the pedal, and add filler quickly. For MIG?? The heat will have to be at max. The wire speed will have to be about 7-8 for that machine.And as for thickness, your machine will weld about 1/8"- 3/16 on multi pass, or with preheat. I used to do it a lot. It's a pain in the rear. My 175A mig is about 10 times better at it- no lie. So much better flow on the aluminum. The little machine will leave your welds humped up a bit, as the arc will not be wide enough to get a smooth flow out on the weld bead. I wish you luck. And, more importantly, access to a tig machine!!! Good luck, Paul.

I like what you're saying! I'm trying to learn to tig aluminum. My progress has been unrecognizably slow, but I took a break from the aluminum to tig together a steel bolt and tee handle tonight, which came out fairly nice for my money!
The idea in these classes seems to be to give us tough welding projects to make sure that we pick up the real skill of it.
I seem to either burn through completely or I don't get full penetration on beveled butt joints in 3/16" plate. Really frustrating at this point. The teacher can run a great bead right in front of me, and so far, I simply fail at it.

[Rojodiablo]

Tanglediver, where in Socal are you located??? You are welcome to come by my place and burn up some tungsten trying to get it right!! Try to remember: Full throttle start, then back it off halfway a second or 2 later. One dip of the rod. Stop. Then, do it again. Soon, you'll see that you won't have to stop and start all over again, you'll be able to keep the arc flowing, and start timing your dips better. It will save you from overheating your part when you are learning. Give me a call, I am in Huntington Beach. 714-801-5514. Paul.

[weldgault]

Originally Posted by hotrodder

Proweld, weldgaults saying (or trying to ) that DCEP breaks up the aluminium oxide layer (electron flow is from -ve to +ve. when the work is -ve (DCEP) electrons leaving the work remove the oxide layer)

with TIG AC polarity is constantly changing and for MIG it's DCEP



everyone, Andys got a little 100amp MIG set. no point in talking about about tungstens!

while theoretically it'll weld Al, in practice the machine isn't powerful enough to weld anything useful- i'd guess 1/8" would be pushing things and thin Al with a MIG isn't fun

it's simply not worth going to the expense of wire, gas etc to try

Its not the electrons leaving the work, but the protons bombarding the workpiece that breaks up the oxides off the aluminum.

[tanglediver]

Originally Posted by Rojodiablo

Tanglediver, where in Socal are you located???

Montclair/Ontario. Thanks for the gracious offer, Paul! The schedule is just so packed these days, I think I can get it, after enough practice! HA!!

Try to remember: Full throttle start, then back it off halfway a second or 2 later. One dip of the rod. Stop. It will save you from overheating your part when you are learning. Paul.

I'll try this at some point when I get back into a tig booth. Thanks!

[William McCormick Jr]

Originally Posted by aczeller

ha... that's weird. about 90-95% of the stuff we weld at work is stuff that me and my engineering budies specify as 304/304L or 316/316L SS. i woudl think that they woudl be able to get it fairly quick then. oh well... maybe they are all just a bunch of pansies. after all, most of them like Iowa State ... hehehehehe

later,
Andy

If you weld stainless steel, or steel or even iron. You can pretty much tell, if it is going to be a durable weld.

When you do aluminum, and I don't care how many years you do it for. You almost have to test a strange, joining of odd shaped materials. In other words I can weld two 1/8" plates together. And not guess. But if I have to weld that 1/8" plate to some other strange structure. I usually give it a test.

Because over the years the best of the best aluminum welders, have time and time again. Stepped back from an aluminum weld, and said "Wow I am the best" Only to hear a rather horrifying bang as a giant crack formed in the part.

I have had that happen on a piece of steel, that I was not fully penetrating, and did not add enough filler wire once. But after that lesson it never happened again.

With aluminum, you often see, a crack, especially where multiple angles or fish mouth joints meet a pipe. Just when you think you made a beauty, you see a crack.

I am not in love with aluminum for that reason. If a steel weld breaks you know it. Aluminum can quietly crack after you are all done.

The only time I had a stainless steel weld fail, to my knowledge was when I partially welded it, because I thought it might have to be repositioned or altered after a fitting. It evidently was ok, but I never knew that, bottom line I never finished welding it. It just vibrated off. No damage or anything. It was a rather comical fishing rig for a truck.

Sincerely,



William McCormick

[ZTFab]

Originally Posted by tanglediver

Montclair/Ontario.

Sh!t...you're right down the street from me. I'm in Upland.

- Paul

[tanglediver]

HeeHee! Hey neighbor!