Welding Tips and Tricks

Hi guys,
I'm taking a tig welding aluminium course at college at night. I mig, braze and tig mild steel at work but want to learn aluminium.
I'm trying to do a butt joint on the flat. I can put down a bead that looks great from the top but i just can't get consistant penetration.
The machine i'm using is NOT modern...

It's the size of a fridge and doesn't have many adjustments.
From memory, HF continuous, amps, polarity and gas ramp down is about it!

The tutor isn't much help. His answer is to 'experiment' with the gap and amperage until i get it right. This would be fine but i only have another eleven three hour sessions before i have to submit five test pieces to get my City and Guilds certificate.
All tests are done with 200 x 50mm 3mm thick strips.
I'm using 2,4mm zirconiated tungsten with about the same dia filler rod. No idea what grade the sheet is OR the rod.
The amperage range is 50hz/265A. The 'fine tune' nob goes from 1 to 10 and i've been playing between 5 and 9 with a gap of between 1.5 and 3mm.
I've tried welding slow and fast and i either get about 2mm of penetration or about 3mm sticking out! EEK!
In desperation i asked if i'm allowed to run a bead down both sides for the test? I'm not...
I tried grinding an angle on one edge, which is allowed That didn't help.

I'm confident i'll be fine doing the fillet weld, one on the flat and one virtical, which i'll probably do vertical up. I've done a few lap joints which look good and the other joint is a tube to flat, which i'm also confident in. I just can't crack the butt joint. (no pun intended)

Does anybody have any tips/suggestions that isn't 'experiment'?

Thanks

Rob

I've never used anything but pure tungsten on older machines with AC. The only other issue I can think of is back purging the joint. All we were allowed to use was a purge plate and even that was insufficient. I ended up passing mine in school welding reverse travel with the purge plate. It allowed the gas to get more directly at the puddle and under the plate where the weld was actually taking place.

I was going by the book trying to make mine look like the pictures. Come to find out, they were allowing not so pretty roots because of the purge limitations. Either way, I kept at it and ended up with perfect samples both front and back.

Hey there ,

Jody made a video on this exact test plate. If you search on the main Weldingtipsandtricks page you should find it.

Mick

Tamjef,
I've just checked the 'assessment and grading' notes and it says twice that "PLEASE NOTE that for any welds in there is NO REQUIREMENT to use a backing purge."
It also says that "multiple runs are permissible". Maybe i should try a root and cap?
The tutor says we should do it in one go though.

Mike,
I couldn't find the videos anywhere as i seemed to be stuck on the forum part. When i went back to the search engine again i found them.
I watched the video three or four times, not because it was so good(which it was), but because i kept thinking i was missing something!

He just zooms down the plate and 'magic' seems to happen!!!!

I'll have to try his settings without a gap and see what happens.
I can't remember what current i was using when i did my first attempt without a gap.

Thanks for your help guys.

I think 5 on my machine is about 130amps. His machine was set at 120hz, any idea what compensation should i make for mine being stuck at 50?

Would using pure tungsten make a difference?

Last night was day four of the course and for the first time the tutor demonstrated how to weld for us.
He put down a lovely looking bead...ON TOP of the joint.
When we turned it over he didn't have full penetration either! I am now SERIOUSLY doubting his welding skill!
This course is more like paying £300 to rent a machine and gas than be tought how to weld
In addition to the five practical test pieces, there is a twenty question verbal test, "explain the underpinning knowledge requirements for the process(TIG)"
Two of us on the course are already employed as welders and we both tig at work, but the other three have never welded in their life. We are told to refer to the course Practical Assessment Handbook, which nobody has seen...
The way things are going i can see everybody failing and a certain head of department going home more than a little bruised...

Hey,

You're right about Jody and the "magic". What that bloke can do with a welder boggles the mind. My take on that video was that its is a "move ,pause, add rod, move" action. I havent had to do it but I believe the technique is in the pause after the move, to allow the pool to sink in. Remeber to clean the edges of your plates as well. Contaminents can be trapped in there as well.

Good Luck. Mick

Hey sorry from the us here not sure on the metric conversion to inches but since you said 120 amps I will guess that is 1/8 inch. At my last job did a lot of full pen aluminium. For 1/8 inch I would usually set the machine at 225 amps would only use about 190 amps. A couple tricks I found us when you first start your weld let the heat soak, you should be able to see your when your bead rops down that's when you know you are getting full pen. If you are doing this test on a bench do not place the piece flat on the table it makes it very difficult to get your penetration, bend your test pieces up about 5 degrees to keep it off the table. The table acts like a heat sync. This also keep keep it from cupping up on you. Purging is not necessary on aluminum but it will help keep the backside flatter and more even. When using a transformer machine I always use pure tungsten
.

Welding Mike,
I'll confess i didn't give the edges any attention, although i was using a stainless wire brush to give the two sides of the weld areas a good brush.
When i pointed out to the tutor that i'd bought a wire brush, he said that he didn't have much faith in brushing as it won't remove oxide as well as the high frequency would...
I look forward to trying Jody's welding method. I just wish we had AC machines at work so i could practise...

ajlskater1,
For conversion from imperial to metric, just remember that one inch is 25.4mm. I've been doing a lot of converting myself. 1/8 is 25.4 divided by 8, and 125thou 25.4 divided by 1000 x 125. Both are 3.175mm.
It's been a LOOOOONG time since i have worked in fractions.
Sheet over here is either in 'guage', or mm.
I've only ever dealt with 22, 20, 18 and 16 guage sheet, which are 0.8, 1.0, 1.2 and 1.5mm respectively. Any profile steel, angle, box etc is all in metric!
I've often wondered what it is like to just work with one unit of measurement...

One thing the tutor seems to have gotten right, is not to weld flat on the bench.
We have two lengths of right angle per welding bay and we have been putting the work on those to lift them off the bench.
Jody also says to bend the joint a little to lift it up. Plus, if the plates bend the other way, downwards, it can make penetration more difficult. It is very possible that as i progress along the weld that the two halves are sagging a little, which would make penetration harder, as i put each side along the ridge of the angle and not across them. My thinking was, i didn't know if welding across the steel would effect the bottom of the weld or not. I must admit i hadn't noticed if the plates had sagged or not.

I've just ordered a pure tungsten electrode and sent my mate this web address as he is doing the same course.

I'll let you know how it goes at the next session in january.

Thanks for your advice and a Merry christmas and a happy new year to all!

Hey there,

I stilk give it a good brush though, cant hurt can it. The only time not to brush or remove the oxide in some MECHANICAL way is when the job will not tolerate any scratch marks. Such as the hand rails and parts that others have posted on here.

Ps thats not my tip about the edges, i lifted it from one of Jodys' videos. Makes perfect sense though when you think about it.

Merry Christmas and a Happy New Year to you too.

Mick

Brushing is good.but not needed. Some parts wont tolerate brushing and most companies will not either because of the time it takes to do it. The first welding job I had back in high school was building aluminum truck boxes and they would not allow you to wipe down the material or brush and was dirty from the oils from the turrets that punch out the parts and the grinders who bevel the edges. But these welds did not need yo be perfect and you would be surprised how the AC balance cleans. The next job I had was doing much higher quality work but they would allow cleeaning but they had these tanks that cleaned the parts before welding took place. It is a nice measuring system but gauge of material is good to.

My welding instructor couldn't tig aluminum either. It wasn't his thing. He could blow your doors off with 6010 and 7018 or flux core, though. Something a lot of people forget when welding for full penetration is how much aluminum shrinks. On 1/8, I bevel the edges and weld them without a gap. It works with the filler rate I am comfortable with. Face bead is nearly flat

Well, i went to college last night. Day five of fifteen.
Don't know if it was using Jody's technique, a pure tungsten electrode, or a combination of both, but after the second attempt i achieved penetration
The tutor said HE wouldn't use that method, because when i lifted i was removing heat and energy from the weld and i'd lose penetration.
What a dick!
I turned the plate over to show him PLENTY of penetration!
In fact, a little TOO much penetration.

One thing i did notice while welding for the first time, was the weld pool actually drop a little. I think up till now i have been moving along a little too fast.
So, after getting a half decent weld for the first time, i was asked to move bays to let two Polish lads share and i moved in with a mate from work to share his machine.
Great, i just get the hang of it and then have to try with a totally different machine...
Second attempt with the new machine/settings and i got an even better weld, but the thing that REALLY cheered me up, was i was able to reproduce a similar weld again!

so, as i was really feeling confident, i had a go at the round tube to plate weld, and was instantly depressed again
I think i dipped the tungsten about every 3mm, that's 1/8th to you lot over the pond, and when i wasn't 'dipping, i was welding the filler to the work or pushing the work into the tungsten.
I didn't make it easy for myself by using a plate about half an inch wider than the diameter of the tube, also, i sat the plate flat on the bench, which meant i couldn't get any heat into the plate before the tube started to 'run away' from the joint. Once i sat it on two more bits of plate it was easier, but still difficult.
Once i've mastered the tube, the only thing that worries me is the vertical up tee fillet joint.
It shouldn't worry me, but after the 'baffling' butt joint, and now the 'troublesome' tube joint, i'm just accepting the fact that i've regressed to being the wrong side of hopeless when it comes to welding ally!


I think next week i'll try this one standing up looking vertically down onto the tube so i'll be able to follow the joint around the tube more easily.

Tubing is more difficult than flat plate. A trick I have used to teach some my buddies how to weld tube is to find the biggest piece of tube I can. The reason tube is had is cause you are constantly adjusting your angle. So with a bigger piece of tube you will have more time to make your adjustments and it let's you get used to doing that and get that motion down. With smaller tube your adjust have to happen much quicker. Vertical up is not that hard just know that when you are first learning it will go slower so you will not need as much amperage. Torch angle is important on vertical up. I have about 15 degrees up help to flatten things out, because gravity will want to push your bead down and tend to build up more than normal.

Well guys...
I went to college tonight, after taking a day's holiday off work because this week i'm on the late shift, full of confidence with the aim of doing a couple of perfect butt joints (fingers crossed), and then getting on to the tube to plate.
But all to no avail.
NO BLOODY MATERIAL!
NO aluminium(or aluminum)
NO stainless, and not a great deal of mild steel either judging by the complaining mig welders!

I went to talk to the receptionist, who is the only permanent college employee i can speak to after normal college hours to get the had of engineering department's telephone number.
She assured me she would get him to call me tomorow. All i can say is, he had better call, because he won't want to be in his office the following day if he doesn't!

£300 for a fifteen 'day' course(one 3 hour session per week).
So far, i've had to buy my own tungsten because they only had thoriated, for steel.
NO material twice.
Still no idea what we are supposed to be learning for the verbal theory test at the end as we are still waiting for the Course Handbook...
One guy, learning just for the hell of it, brings his own ally plate, filler rod and tungsten from home.
Oddly, this is the ONLY guy they should be worried about keeping happy. He is a gunsmith...

Do you have ths kind of high quality course where you all come from, or am i just lucky?


AJ, maybe i'll be able to use your greatfully received advise next week...

If it all goes pearshaped next week, can i call on you all for backing up my plea of 'justifyable homicide, as i am getting close to breaking point'?
I'm developing the same twitch that Chief Inspector Dreyfuss did, and we all know how THAT ended...

The page address is

http://www.weldingtipsandtricks.com/tig ... num-2.html

The heading is "Tig Welding Aluminum settings on "Old as Balls" Welding machines"

The picture is one of the four machines at college!
I wonder which decade 'Balls' were invented?

Worryingly, i think the machine i have been using pre-dates 'Balls', as it has even less nobs and whistles.(pun intended)

I'd be hot like a two-dollar pistol if I'd put out that much scratch and the school couldn't even provide the materials.

Document all this. Demand a rebate. I can take a 20-minute drive and collect enough drop from shops to do everything your course covers, and not work up a sweat, or spend a penny.

I have zero experience with welding schools. I'm a combination of self-taught, and on-the-job taught.

I've encountered people coming out of school who are ready for the job, but that's not the norm. I've encountered more people who can weld just fine on the test bench, but when they are put in position, they fold. The training of many schools does not really prepare people for real-world work, but only the basics so they can quickly learn real-world work.

In college, my advisor was the head of the Industrial Technology Dept. and a PhD. He made it clear; College does not teach you how to make a living. It teaches you how to LEARN to make a living.

Steve S

If they don't have material by next week I would demand my money back. You are there to practice under a trained person who can help you learn to weld. And from the sounds of it your instructor is worthless. If you can't get your money back I would definitely go to some local shops, I am sure they would give you some scrap or at least a very good deal so at least you can make the most of your time there. I never went to school I am mainly self taught. I am of the same opinion as Otto is about. At my last shop were I was the lead Guy, when we were hiring I would not even give a test to someone that did not have 7 years or more or real world experience. In my experience people straight out of school are not well enough practiced to pass a bench test. I think this speaks to what your are encountering. I believe schools aren't doing their jobs properly training people, which is stupid because you guys pay good hard earned money on a sub par training.

I went to welding school for 18 months. I burned rod 5 out of 6 hrs every day, plus an extensive blue print and math for welders course that was put out by Hobart. The machines were all old Hobart rigs.

When I went for my first job interview out of school, I not only passed their test, but beat the guy who gave it to me and continued to surpass him from there on out. My only advantage was having some years in sheet metal so i had a lot of layout and tool experience. Our welding instructor was an old school union iron worker, who inspected your welds with a bright light and a magnifying glass, and would fail you for a slag hammer divot even after your test passed destructive tests.

Another fellow I went to school with was adept as well and landed a great job with the Railroad.

There was a lot of problem children in trade school. There was guys there with juvenile records that were court ordered to be there. MAny who would cheat their way thru tests by grabbing a good one from the scrap bin.

When I interview people out of school, I can spot talent before they even strike an arc, just by the way they present themselves and how they dress and by looking at their equipment.

I showed up for my test with this. My school issue, Fibre-Metal hood. Best head gear of all so far. It would still squeeze your head like a peanut after 20 years. I used this up until about 2 years ago. I left it on the back of a customer's boat and it is 100 miles South of here somewhere. He's supposed to bring it by next time he is up this way. Ugly as all get out and I knew I looked green showing up with it.



Tube on plate is one of the easiest welds to do in aluminum if you don't over think it. I can teach most people how to do it in under a day, just by teaching them eye to torch perspective and how to focus on that and amperage control on the fly.
Here is one my son did on his first day using a foot control. 1-1/4" Sched 40 on a 1/4" x 4" flange.


A good, hands-on instructor should be able to show someone how to at least get the feel for it. The problem is, most instructors are not well versed in all the welding processes, especially TIG. Ours admitted he was mostly a 7018 stick welder/oxy-fuel and just knew what the beads were supposed to look like with the other processes.

Are you using a foot control? If so, the first thing you really need to learn for welding in circles is how to pulse the pedal. When you are setting a puddle, should be close to floored, then back off the pedal as you set up for the next puddle, even if you have to back way off. It will buy you time until you get your timing/torch angle tighter. They didn't teach us this in school per the course, but we had an aluminum welder come in and this is what he showed us and suddenly, everyone was turning in much nicer samples.

Hey there,

Just a side note on experience. Ajilsskater said about only hiring people with 7 or more years of experience . I believe that it possible to get an excellent employee with a lot less experience than that. Providing they have suitable skills and are willing to learn. I cant count the number of people who rocked up to work saying they've been welding for years and turned out to the worst welders under the sun. On the other hand, one of our apprentices, who never picked up a welder untill the first day of his apprenticeship , within 6 months turned into one of the best welder/workers in recent years. He won state apprentice of the year 3 times in a row.

Unless you need someone to weld nuke pipe on their first day, the need for an ultra experienced person is somewhat less. People with less time under their belts can be easier to train because they havent learnt bad habbits yet.

My opinion, no one elses.
Mick

That's true about more experience not necessarily being better cause I have seen that a bunch as well, just had really bad luck with kids straight out of school as well.

Hey,

Very true mate. I reckon you have to judge each case on its merits. But thats a luxury not all can afford. If your company has different levels of work, its good to be able to put the pups on the "easier" jobs and move the bigger dogs up the ladder. But i do believe it is important to let your people 'grow' because nothing worse than not be allowed to do a job because someone else thinks you wont be able to. That happens at my work abit, mainly with Aluminium tig jobs. they have their go to men and no one else gets a look in, regardless of skill.

To get the post back on track, (sorry for hijack) When I first started my apprenticeship, the training organisation (term loosley used) was on a measley budget. The would almost count the electrodes as they handed them out. And they would go to the scrap yard and buy a tonne of scrap steel and you would have to scratch through it to get a bit to weld up.

Mick

ajlskater1 wrote:That's true about more experience not necessarily being better cause I have seen that a bunch as well, just had really bad luck with kids straight out of school as well.

I agree with you on this point as well, especially within the last 10 years or so and it seems to coincide with the attendance levels dropping in trade schools these days. I have had kids show up without their shoes tied, without their own hood and hand tools and ask to borrow mine for a weld test. Worst yet, they got past our company owner who passes them on to me to reject.

Trainable and ethical tradesmen have an air of industrial astuteness about them and this is especially true with welders, I think, or at least as far as it applies to welding. All of us who went on to be pros out of welding school had it. It made for a smart and efficient environment, even at the entry level.

I'll attempt to summarize by saying welding on the school bench requires hand-eye coordination, and passing a print-reading test requires study skills.

Welding in the field, on a real job (unless you're doing repetitive production welds in a fixture) requires mechanical aptitude, spatial orientation skills, general intelligence, and a "can-do or will-learn" attitude.

Not everyone who can pass a 6g in a class is cut out to weld for a living. (Maybe that where we get some of these teachers?)

Steve S

Hey,

May I add that not everyone who fails a 6g at school should be thown on the scrap heap.

Mick

weldin mike 27 wrote:Hey,

May I add that not everyone who fails a 6g at school should be thown on the scrap heap.

Mick

Also true.

After lat weeks farce, my dolls were truly thrown out of the pram and i had a constructive discussion with the head of engineering, who, apparently, didn't know anything about my...problems...
All has been sorted now(hopefully).
Material was ordered for the wednesday class.
The course handbooks were printed for the wednesday class.
The tutor is now in possession of the verbal questions so he can now start teaching us what is needed.
AND i have the direct line to Ben, the boss, should i need to contact him again.
The tutor has been asking for acid etch to check penetration since day one, and Ben told me that their welding supplier had never heard of it!
I can only presume that they have been using the welding department of a flower arranging shop or something!

I can certainly vouch for 'years of experience' NOT guaranteeing being any good.
Last night at work i spent 8.5 hours linishing welds on box covers. About 4 feet long by a foot wide and high. The long sides and top are one piece with the two ends tigged on. We fuse all around the end not using any wire and then there is an upside down u channel welded to the inside of both ends and an angle stitch welded to the inside of the sides. I did around 40 of the 60 welding in the end pieces, and Paul, who has been here for about ten years did the rest. I don't know who did the u section and channels.
I slowly went along the joint at 50 amps and produced a neat rounded weld. Paul's welds have dips in them, has burned away the top edge or the bottom edge and look crap. I had to keep adding wire as i couldn't manage to linish the dips and missing metal back on. Maybe it is a sign of my lack of experience ?
I've been working here for about a year and a half, and when i first did this job, about nine months ago, when i started linishing the cases i was politely asked to stop, and concentrate on welding, as my linishing was...er CRAP!
I thought it was good, until i saw what one of the other guys was left with afterwards and felt like creeping into a corner and hiding!
Since then i have had to linish some smaller jobs that had to look perfect and now i can remove metal like a pro!
I feel that having to dress my welds has made me a better welder as it makes my life easier when doing so.
One problem we have here, is that some of the welders are never made to linish, because they can't so i think their resulting weld finish could be better as they never have to dress it off.
Our work is mostly large production runs so often one shift welds and another linishes, which would be fine if it was shared out, but the other shift has a gobby pushy foreman and often gets his way, so his guys get the easy work...
I wouldn't mind if Paul made up for his shitty welding with speed. But he is S L O W !
For example, three foot(ish) oval tube with a flat plate welded on both ends. In a jig that holds two tubes/plates, on a pivot so you can weld one end and then spin it around to do the other.
My first day, 282, second day 322. His first day 122 followed by 130. That's bad enough, but i was on earlies, 7.5 hours worked and he was on lates and worked 8.5 hours. We work an extra hour so we can finish early on a friday, 5:30 instead of 11:00. So, several years of experience doesn't mean a better welder...
Not all welding schools are bad either. When i was at this same college in 1987, the two tutors there could weld! REALLY well! Although they both had different ways in doing some things, which would end with one asking why i was doing something the way i was and having to answer that "Dougie told me to", followed by Why was i doing it like that, "because Derek told me to."
WHich in itself wasn't a bad thing, because it tought me, as we all know, that there is more than one way to weld the same thing!