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velotux
04-26-2010, 02:13 PM
Hi AZ krew.

I have a DC Inverter arc welder that can be used to tig weld steel and stainless with the addition of a tig torch, valve and gas. I have been told I can not weld aluminium with a DC tig welder. I realise that ac tig welders are the norm. Bear in mind I am not a coded welder. I understand also that it is not common practice, but I do not accept it cant be done. There are perhaps good, and well founded reasons why it shouldn't be done commercially and professionally, but I would like to weld up some 1/8" wall 1 1/2" box 6061 occasionally for those "special" projects. If making ally zombies becomes a habit I will invest in the equipment, but are there any reasons why I should not attempt it for a test bike. The inverter has a max output of 90A.

I look forward to, and appreciate any comments on the matter.

Many thanks and best regards.

Tim

Odd Man Out
04-26-2010, 05:46 PM
You have nothing to lose by trying it other than a bit of 6061...

To my knowledge, AC is the only way to TIG AL, DC will not work.

PeterT
04-26-2010, 06:02 PM
At the least if you try it, and post the progress pics along the way, then we will all know whether industry has it wrong, and you have it right!!

If it doesn't work, then we will all see why it doesnt work!

PeterT

badcheese
04-27-2010, 01:26 AM
I used to weld 1/8" wall 6061 T6 tubing for a living. Our shop was outfitted with Miller "Syncrowave" machines. These were massive DC inverter machines with oscillators, so you could weld with straight DC, pulsed DC, or AC, and you could adjust how much of the cycle was electrode positive and how much was electrode negative. I always welded Al with an AC cycle set to 100% electrode negative (if I remember right - it was a long timew ago), which gives a waveform that was essentially a high frequency pulsed DC. Sometimes I would TIG a bit of mild steel using straight DC to make tooling, then go back to welding Al and forget to change the settings back. It worked terribly, but I don't remember what happened. I think maybe the arc wandered all over the place.

The bigger problem you are likely to have is current. Even though Al has a much lower melting point than steel, it takes much more current to get a puddle, because Al conducts the heat away from the area much faster. No joke, I typically ran my machine at 245 amps for welding 1/8" wall tubing, and no one in the shop used less than 190 amps. I doubt you can get a puddle with 90.

But I encourage you to experiment!

I really enjoyed TIG. It was very clean, and didn't throw sparks. You could weld in a tuxedo if you wanted, and you wouldn't put holes in it. However, at 245 amps it would give you a sunburn right through your T-shirt, and the sound of the arc was like a hammer drill. Wear sunscreen and earplugs!

velotux
04-27-2010, 12:10 PM
Thanks for the encouragement and information. I will give it a try on a length of material I was given which is close to what I will be using for the bike. I do not hold out much hope from what has been suggested though, but not a lot to lose. After all if we didn't experiment Brad would be riding around on a penny farthing in a top hat, and we'd all be welding with bellow fires and red hot pokers.

Thanks and all the best.

Tim

FlatBlack
04-27-2010, 01:37 PM
Hi Tim,

This does not relate directly to TIG welding, but on page 92 of "Welder's Handbook", Richard Finch talks about arc welding aluminum with a DC arc welder. A while back, I found some aluminum rods at a hardware store. On the package it says that it "works on all DC welding machines". Since I have a Lincoln AC/DC arc welder, I bought some thinking I would give them a try next time some aluminum thing breaks.

Since I have not personally tried this, I do not vouch for these rods or for the advice of Mr Finch, but since you are experimenting, this might be something else to try.

Cheers,
Bill

mausball
04-27-2010, 01:54 PM
Bill, keep us posted when you finally try your Al welding rods. I'm very curious about them as well. I've seen them advertised for casting repair, tube repair, tank (!) repair, and others.

velotux
04-27-2010, 02:23 PM
Hi Bill.

Many thanks for the information. I have been considering these. I have seen 2.5mm Aluminium sticks for DC arc welding on Ebay. They are available in packs of 5 for 5. I can find little information on how good they are. I will get hold of some for experimentation and let you all know how I get on. I have just received a reply from a post in a welding forum. Apparently DC is not used in tig welding Aluminium because of the lower melting temperature. A dc arc is apparently hotter, and you would have to weld particularly fast and so is hard to weld accurately and well. Also Aluminium has a thick oxide layer that the AC nature of the arc breaks up and penetrates as you weld giving a better quality of weld. A number of other points raised earlier by badcheese. Like pulsed DC were also mentioned and this is beyond the ability of my equipment. In short it was suggested that unless you have top notch industrial equipment and are a very experienced welder that I would be wasting my time. I am dissapointed of course but one must bow to knowledge and experience. I have learned a little more about the art of welding in the process so all is not lost. And in the process as is usual with life, when one door closes there is another option waiting to be explored. I think that trying these aluminium stick rods is going to be my main route of investigation for the moment. Let me know how you get on if you try them Bill. I have not given up on tig welding and will continue to explore and learn welding but I have a feeling for the moment anyway, it is beyond the equipment and ability I have.

All the best.

Tim

bustoff
05-01-2010, 11:05 PM
I use the AL sticks. They work fine. You just need to remember to clean the metal right before you weld it. Aluminum oxidizes very rapidly. I usually get all set-up and the last thing I do before turning on the machine is to clean the joint with sandpaper. I'll even have my gloves and helmet on before cleaning the metal. You weld DC electrode positive.
I've had very good luck with aluminum stick welding.

velotux
05-02-2010, 03:13 AM
Thanks for the information and tips bustoff. That is good to know, and thanks for sharing your experiences with a aluminium sticks. I was hoping my sticks would arrive to try them this weekend but they havn't yet.

All the best.

Tim

64c10
05-02-2010, 09:50 AM
not sure if it will apply but with my Mig welder you have to reverse the contacts on the gun when you go from steel to aluminium. you might need to do the same with the Tig. all of my Tig welding was done with a dedicated Tig machine.

velotux
05-02-2010, 10:54 AM
Hi 64c10.
Indeed the technical data for the Aluminium sticks states electrode positive. I have no idea about switching polarity for different materials. Perhaps someone could shed some light on this.

Cheers.

Tim

64c10
05-02-2010, 05:49 PM
switching polarity refers to changing the ground clamp and electrode. this will depend on your welder, most migs this is under the side cover with the wire spool. most buzz boxs these are located on the front bottom. most manufactures have some sort of tech data to show you.

velotux
05-03-2010, 03:55 AM
Hi 64c10.

Sorry, got our wires crossed somewhere. I know how to switch polarity on my welder but absolutely no idea why. Some sticks like the Al sticks have polarity to be used indicated on the box, my general purpose steel sticks do not. I would like to understand this more.

Cheers.

Tim

John Lewis
05-03-2010, 07:33 AM
One day nothing would weld right. It looked like bird droppings. Then it would burn throuf. Bad bead Yu name it. Then I twigged. Polarity was wrong. I'd plugged into the wrong sockets on the welder. DOH.

John

badcheese
05-03-2010, 08:47 AM
As I understand it, welding electrode negative results in more penetration, while welding electrode positive results in more "cleaning" action. Supposedly this has something to do with the direction of the flow of plasma in the arc (positive to negative), which is opposite to the flow of electrons (negative to positive). As velotux said, the oxide layer that forms on aluminum is tougher than the oxide layer on steel.

mausball
05-03-2010, 09:31 AM
As I understand it, welding electrode negative results in more penetration, while welding electrode positive results in more "cleaning" action.

Something like that. I do know that TIG machines for AL use high frequency AC with variable duty cycle to push the overall signal average more positive or negative, which still maintaining the back-and-forth that keeps the AL clean.

25hz
05-03-2010, 02:17 PM
Some basics:

1) The majority of the heat is generated where the electricity "lands". Electrode -ve/straight means the arc flows from your hand to the work piece. The heat is concentrated at the workpiece. Electrode +ve/reverse means the arc flows from the workpiece to your hand and the heat is concentrated at your hand.

2) You can't compare TIG welding AL to ARC or MIG welding AL, at all. Different current, different setup and different filler wire.

3) A weldable AL alloy melts somewhere in the 1200 to 1500 F range. AL oxide melts at 3500F or higher.

4) AC for TIG welding AL is required because the current cycles from electrode -ve to +ve. It has to. The electrode +ve "pops"/cleans the AL oxide so on the next electrode -ve cycle the arc can penetrate the material and weld, and the cycle continues.

5) MIG and ARC can weld AL but the machines are set up electrode +ve so the current flows from the workpiece to the torch. Why? Because the reverse current flow helps blow off the oxide layer. The filler rods for this process are designed to take the heat.

6) Trying to TIG AL with DC and either the heat will not melt the oxide layer in elecrode -ve and you'll burn through (or it will look hideous), or with electrode +ve, the electrode will melt, slag off and contaminate the bead when it falls off the torch.


In any case, if you want to know what is going on when you weld, and why you have to use the settings you do, you need to go someplace with the right answers. Regardless of how friendly or helpful people will try to be, you can get a lot of wrong or bad answers. You need to go to a search engine, and type your question in the box, and hit search. Then, you start reading, and you keep reading until you understand what you're reading. Even if you don't understand what you're reading, you can still weld - just follow the directions for the settings. Print them out if you have to. Once you've welded for a while, go back and search and see if you understand the "why's" now that you have some real experience. At the very least, understanding the "why" and the "what" helps you to troubleshoot when things are going wrong.

It also really helps to learn what the terms and names actually mean, because most people get those wrong too. "MIG" for example, isn't "MIG" unless you're using gas. You aren't "MIG" welding when you are using a spool of flux core wire and no gas. That's just a single, simple example, but if you are trying to understand something, using the wrong names doesn't help straighten anything out.

shaker
05-03-2010, 11:36 PM
Some basics:
It also really helps to learn what the terms and names actually mean, because most people get those wrong too. "MIG" for example, isn't "MIG" unless you're using gas. You aren't "MIG" welding when you are using a spool of flux core wire and no gas. That's just a single, simple example, but if you are trying to understand something, using the wrong names doesn't help straighten anything out.

Not to sound like a knowitall, but if we're going to correct people for not using the proper names then....

It's not MIG (Metal Inert Gas) it's GMAW (Gas Metal Arc Welding)
It's not TIG (Tungsten Inert Gas) it's GTAW (Gas Tungsten Arc Welding)
There are two types of Flux Cored Arc Welding
FCAW (Innershielding) and FCAW-G (Outershielding)
It's not ARC (every process just mentioned is arc welding) or 'stick' welding, it's SMAW (Shielded Metal Arc Welding).

Again, no disrespect intended. I work as a welding instructor/CWI (newly minted) and I too like to see the proper names and terms used. :cheesy:

Be cool.

-shaker

25hz
05-05-2010, 09:52 AM
Well, as a "welding instructor", you should also know that GMAW, GTAW, and SMAW are all general categories of welding mechanics and processes, and there are multiple subtypes in each. Subtypes like MIG, TIG and ARC/stick. Those are all standard, acceptable and understandable names. They are also EXACTLY the names that are written on the side of my ARC welder, TIG welder and MIG welder. Naively perhaps, I'll assume that the welding machine manufactures know what it is they're building. Extremely few people that weld, even for a living, use the smarmy engineer-invented and clumsy acronyms that outline the general categories. While the term "ARC welding" does describe any process of fusing metal together with an electric arc, in my paltry 35+ years of welding, I hear the term "stick" once out of 20, and the other 19 times its called "ARC".

Odd Man Out
05-05-2010, 01:40 PM
Shaker
Welcome to the forum -- hope to see what you are up to. Glad to see your input...

25Hz
Glad to have your input. You are widely respected for your work in the recumbent world. Please don't get your feathers ruffled if someone gives input to what you have said. Life is too short. :punk:

velotux
05-05-2010, 02:17 PM
I concur. It is great that we have the benefit of folk who are willing to share their knowledge and experience, and we have those who are searching to expand their knowledge and develop skills who can only benefit from that. It is also great to have those that say "The stick thingy sparks for a bit and then its stuck, and my metal falls apart". This is a great well rounded community for all skills, abilities and interests in creative bike building. It is good that the experts can tell us what things are called and how it should be done but equally we should all be, and generally are, sympathetic and very helpful to those who are in the early stages in their bike building enjoyment, and the varied people that are enjoying the thrill of it. For some builders this may well be the first time they have had any fabrication experience whatsoever. Others are without doubt professional fabricators. I hope this diversity in skills, ideas, resourcefulness , creativity, imagination, sense of community, helpfullness and inventiveness thrives however we come to here about it because its wonderful, and for all to enjoy.

All the very best one and all.

Tim

shaker
05-06-2010, 12:19 AM
Well, as a "welding instructor", you should also know that GMAW, GTAW, and SMAW are all general categories of welding mechanics and processes, and there are multiple subtypes in each. Subtypes like MIG, TIG and ARC/stick. Those are all standard, acceptable and understandable names. They are also EXACTLY the names that are written on the side of my ARC welder, TIG welder and MIG welder. Naively perhaps, I'll assume that the welding machine manufactures know what it is they're building. Extremely few people that weld, even for a living, use the smarmy engineer-invented and clumsy acronyms that outline the general categories.

I'm sorry if my post offended you in any way. I meant no disrespect. On the contrary, I have great admiration for your work. You have forgotten more about bike building than I will probably every know and I've learned a lot from your website and previous posts. I hope to one day build a trike half as cool as yours or Brads'.

But my point was that if we're going to direct someone to educate themselves about a certain subject, shouldn't we at least refer to them by their correct process designation versus industry slang/obsolete terms? Isn't that the same example that you were using when explaining the difference between GMAW and Flux-cored to the op?

Anyway, I don't think that it is naive to believe that welder manufacturers know what they are building and I agree, the terms Stick, Tig and Mig are the most common ways to refer to those "smarmy engineer-invented and clumsy acronyms" SMAW, GTAW and GMAW. That doesn't change the fact that those terms are either industry slang or obsolete.

What the marketing dept decides to put on the side of the machine is their business. My neighbor has a Lincoln powermig3500. Should I start calling GMAW 'powermig3500' because of that? I guess I could. Perhaps I will. :cheesy:



While the term "ARC welding" does describe any process of fusing metal together with an electric arc, in my paltry 35+ years of welding, I hear the term "stick" once out of 20, and the other 19 times its called "ARC".

Perhaps we interact with different caliber of welders. The x-ray certified structural/pressure vessel welders I work with (and am) refer to it as "stick" and then SMAW. And I have never written nor seen a weld procedure, PQR or weld inspection report refer to it as anything other than SMAW.

On a side note, I thought the advice that you gave the op was great. I had written something similar to him the day before about his machine and it's capabilities. I'm glad that the info is out here for others to learn from. I'm kind of disappointed that my tongue and cheek post derailed a very informative post from it's original intent.

Again, I apologize to you and the op. I meant no disrespect. From the info you provided you are obviously a knowledgeable welder.

Be well.

-shaker

Odd Man Out
05-06-2010, 11:28 AM
So uh, hey Shaker
What do you know about DC TIG welding?
Also I have a question for you and anyone else who is knowledgeable about welding alumin(i)um = and it is this:
Can 7000 series aluminum be welded and if so how?

zobman
05-06-2010, 06:35 PM
I just wish I could weld better and have bettter looking welds!!!!! What ever name you call it!!!!!

25hz
05-06-2010, 06:53 PM
Shaker
Welcome to the forum -- hope to see what you are up to. Glad to see your input...

25Hz
Glad to have your input. You are widely respected for your work in the recumbent world. Please don't get your feathers ruffled if someone gives input to what you have said. Life is too short. :punk:

My feathers aren't ruffled. I'm not offended in any way. For me, it's about information, not egos. Put good information into the hands of people, and they can do amazing things. That's what I'm hoping for. The right information to get into the hands of someone who can put the pieces together and change everything for everyone. Proper names make that happen. Using the wrong names for things doesn't clarify or expedite.

As for "calibre of welders", I could take offence to that, because I know a lot of welders that can lay down beads in just about any weldable material that look so good you'd swear they were edible, and they don't care about, or use, fancy acronyms. But I'm not offended. I have friends that were pressure vessel welders, including the dude I work with who was doing a bunch of work for some SS piping/tanks that was going into space for something. I work with, amidst and often, around lots of talkers and engineering types that like to use fancy acronyms and terminology. It's really no surprise to me that the welders I know, and the people I gravitate towards and associate with, operate on much the same principles as my dad did. "Don't tell me what you know, show me what you know". Reading specs or a blueprint is fine to get nice terms in the "??AW family", but when we all strike the arc, you know what we call it? MIG, TIG and ARC. Apparently using more pedestrian terms for our calibre of welding seemingly hasn't affected our ability to weld at all, and it's also made it easy to interact with other people who are interested in getting work/workorders done or learning to weld themselves.

If people get formal welding education (I didn't) they'll learn all kinds of fancy terms, but they aren't required to weld or be a welder. Of all the people I've taught to weld, none of them weld as a profession and all I needed to do was explain the descriptions written on just about every welding machine out there, and in their manuals. If they could use a pen, and listen, they were away to the races. Common, correct, usable terms. That's the point.

Odd Man Out
05-06-2010, 07:40 PM
Hey 25Hz
Can you give input concerning my question about welding 7000 series aluminum???????