Welding Tips and Tricks

I'm new to tig welding aluminum, been welding in DC for couple of years. Now we have a new Kemppi Mastertig 2300 AC/DC tig in our company and started learning how to weld aluminum. I've read all about tig welding aluminum on Jody's excellent site and watched many videos.

So far I've managed to weld on plain aluminum plate and can get the stack of dimes appearance easily. Forming the puddle and feeding the rod is OK. No problem in there. Now I started butt welding two pieces of aluminum together and the difficulty of welding aluminum hit me like a thunder. Prior to welding I carefully cleaned both al plates with a stainless brush and cleaned with acetone. I have big difficulty in starting the weld and in tack welding two pieces together. Material I'm using is 1/8" thick, 4043 filler and 15cfh flow of argon. I'm welding with about 70A current (varied the current also from 60 to 90). AC frequency is 100 squarewave and tried also different balance settings without luck. The problem is that the arc wonders in between these two plates and does not stay in the middle which is actually very easy to do when welding stainless - or I have never observed any difficulty. Pushing rod to this "melted aluminum" part ( in between two plates) results as the rod forming black staff and it just does not work. Every now and then tagging works ok but more often result is very bad. I can see that there is no clear melted part of aluminum in both plates where I can push the rod and this is driving me nuts.

Any ideas how I can solve this problem?

Crank that power up!!!

Half your power (when balanced) is flowing in the wrong direction for heating the Aluminum.

Set your balance a couple ticks toward "penetration", and turn the current to about 160-180 amps. (Seriously.) You need at least a 3/32 tungsten, preferably 1/8 for this heat. 3/32 should be fine with a Lanthanated tungsten. Pure is more likely to puke at these amps. Let that arc jump back and forth until you have molten Al on each side, then stick the filler right in there. Feed it fast and hard until you have a puddle bridging the pieces. In fact, you have to feed Al pretty quick and move on in general.

The arc wander is common in HFAC. Keep it close in until you establish a puddle. Once the puddle is the high point in the arc path, the arc will stabilize.

You're not using a helium mix, are you? Inverter machines like the stuff, and you'll be fine. Transformers, even square-wave, not so much. Causes arc wander. I've seen very experienced welder do OK with it, but not for the beginner. (If you're getting good results running beads on plate, I'm guessing this is not the problem, but worth a mention.)

Steve

BTW, I recently borrowed a new, top-of-the-line lincoln inverter with computer-controlled 400HZ AC. It damn near didn't need me! Welded like a dream!

When I buy my own TIG machine, I'll be looking for stability like this. (I do this for a living, and the machines are supplied. All I gotta bring is my torch, and I haven't even needed that on the last few jobs. Still, I want my own. They generally don't want you to learn on the job, and there are still many things I want to learn.)

Steve

Thank you very much for your advice Steve!! I'm using argon and helium mix is not an option at least at the moment. I will rise up the current today and give it a new try - after some time without luck I was out of ideas. I will let you know the results. One major problem is that I'm not having a foot pedal what seems to be a must when welding aluminum. The handle has a pot for adjusting current but that is totally unusable since I cant grab the handle so that the pot would be easily adjustable while welding.

I have no experience about the Lincoln 400Hz machine you have access into but I believe these modern machines make the welding process a lot easier to handle. It just does not courage me much going on with aluminum with you comment "It damn near didn't need me!" since this machine I'm using is also from the top of the line .

This Kemppi Mastertig has a "mix" feature introducing pulsing while welding aluminum in AC. The pulse frequency range is from subHz and up to the 10Hz (+ some other adjustment parameters for this pulsing). I tried to look for information about this but found nothing. What could be the application when this is needed?

At home I have Kemppi's DC inverter tig which does not have pulsing or any other nice features. But I'm well capable of doing what I need with motorcycle projects but with AC missing I can't weld any aluminum. So just like you, I'm looking also to buy a new AC welding machine and Everlast 250 is looking as one option. Kemppi's machine is out of my budget since an air cooled 230A Mastertig costs about 4600$ and it is just an air cooled version. And, the foot pedal for this is close to 800$!!!! Water cooled 250A everlast is just half of this price.....

Steve, you were 100% correct, pumping up the current stopped the sooting of the puddle (sorry for bad english - I'm from Finland and therefore my writing may not be easy to understand...). Interesting, too cold or a bit dirty and the end result is quite the same.

Thank you for your help!

I'm glad I could help.

As to your English, you write it better than most Americans speak it.

Pulse features can be very handy when welding thin sections, outside corners, or near the edge of something where you don't want to break the edge. It gives you little bursts of full power to do the work, backing off to a backgound level to keep the arc going and the piece near fusion temperature. It's sort of a precision version of what you do with a foot pedal.

A few months ago, I welded a great deal of aluminum instrument tubing. I have some pictures posted here somewhere, and if I can track them down I'll link to them here. This stuff was .049" wall, 3/8" 6061-T6, and it was all socket weld. We had the fittings custom-machined for this, as apparently nobody welds enough of this for making them to be profitable. The fittings were all sch. 80 for 1/8 " pipe, bored to the O.D. of the tube. They were very thick and heavy in comparison to the tube, and there was a fine line between "enough heat to weld" and "enough heat for the whole mess to drop off on your foot". I had the machine set at 150A, pulse at 4HZ, pulse width at 20%, and background current at 40% (for 60A). With the advantage of a foot pedal to limit the max current, it was fairly easy to control. I'd keep the arc on the fitting most of the time, and once I was used to the 4HZ rythem, I could move the arc to the joint for two pulses, feed the rod at the second pulse, and move off.

Jody has a video or two on the subject, as well. It's intersting stuff, and he's a wonder to watch on some of this stuff.

Steve

Zeb,

I bumped the topic "TIG on aluminum" to the front page. It should appear just below this post (as I post it). One of the pictures is missing, so tinypic.com apparently lost it, but you'll see what I was talking about. There are a couple of pics of the whole project, there, too, as well as a close-up of a 3" Al pipe weld.

There is some discussion in that topic you may find worth reading, as well.

I hope I don't come across as a show-off here, as on this job my skills were probably a little BELOW the average of the crew. I was surrounded by, and learned a lot from, some excellent welders. I also hope you're encouraged to keep practicing. The more skills you aquire, the more valuable you are to employers.

Steve

All I can say is WOW! Your skills in welding aluminum is from another universe if you compare it to what I am doing at the moment. It was interesting to read about the T-weld (welding another piece in 90 deg angle to another) welding principle since I noticed the same thing - two arcs on both pieces and it is very difficult to get it going. I'll keep on practising buttwelds first. My greatest difficulty is to select the correct current for each workpiece but now I have a good idea how to proceed. It's a bit surprising that I am doing better with 0.040" thick aluminum than with thicker and I guess this is because of incorrect settings. Absolutely the biggest problem I still have is the black soot appearing in the welds in starts - when I get the puddle going after first successful rod tip it is ok after that.

Like Jody told - welding aluminum makes you also a better welder of stainless and other steels. How true!

BTW, I am building harleys as my hobby and that is why I am so eager in learning aluminum. Stainless and steel welding feels now like childs play with tig - even I still have a million things to learn. With stainless I can weld parts together and welds seem acceptable to me.

But I will definitely keep on practising, that is for sure. Thank you again for your help, really appreciate it! Will post new questions as soon as I run against the wall again (should not take too long).

Welding became better by increasing the amps but today after trying to join two pieces of aluminum resulted again as a total mess with black aluminum spots and smoke after starting the weld. If I just kept going past the ruined weld it again became a bit better and I was able to "glue" the pieces together. I started to get really frustrated because now I had the gas lens also in place which was suggested by one aluminum tig welder.

Before totally giving up welding aluminum, I took our new welder at home to check if the fault was in the argon. First attempt to join two 1/8" of aluminum and it was like butter - no smoke or black round aluminum balls. Very nice weld with 1st attempt! The difference between good and bad gas is so big that it is hard to believe. I trained welding aluminum for 5-6 evenings with this bad gas, wondering the difficulty of welding aluminum... This is just my luck - first time learning aluminum welding and my gas is bad.

One thing about Tiggin aluminum is it is kinda hard to get the hang of, but once you do it is soooo easy. It is soft, clean, solidifies fast and it just goes where you want.

Hi there,

Thats a big problem when you are learning. You tend to think that things "should just be that way" or that its your fault. Always ask questions and don't just keep ploughing on.

Mick

capozzoli wrote:One thing about Tiggin aluminum is it is kinda hard to get the hang of, but once you do it is soooo easy. It is soft, clean, solidifies fast and it just goes where you want.

I wouldn't say that I am good with aluminum but now with good gas I understand what you mean. I just need the foot pedal - it was ordered and we will receive it next week. As compared to my previous attempts with bad gas, now it is a lot easier.

weldin mike 27 wrote:Hi there,

Thats a big problem when you are learning. You tend to think that things "should just be that way" or that its your fault. Always ask questions and don't just keep ploughing on.

Mick

That is so typical of me - I just keep on thinking what am I doing wrong and try to change something and try again. What was very strange (at least for me) was that when I put a beam of weld on the top of 1/8" al plate, it was very easy to make a good bead with a stack of dimes look. No sputtering or anything that would relate to gas being bad - just the opposite. But, every time I tried to join two pieces together it was a mess. Rising the current helped some like Steve suggested but couple of days later it was bad again. Bad gas was not 1st on my list. At least I learned something.