Doing a welding course - notes as I go

[PaulN]

Besides welding skills that whole picture is a work of art in itself!  😎

[landroversforever]

On 2/7/2020 at 10:42 AM, elbekko said:

Yeah, light is a huge help. Although the location of the light is important, I've found if the lights get into your helmet it doesn't always shade properly (and that's with a proper ESAB one).

Have thought about getting something like this: https://www.amazon.com/Steck-23240-Mig-light/dp/B002YKIM6S

Check your battery! I thought it was the light in the back of mine that was stopping it (I've even got the lights above the bench so I can switch them individually). I swapped the battery out and realised it was the original 6yr old one! 

[elbekko]

Brand new helmet, so should be fine. The one we had before was one of the solar powered ones, useless. Didn't get used enough to keep a charge, and not easy to give a quick charge in the pouring rain...

[FridgeFreezer]

Well another evening of welding has occurred - you can really see the progress in the pile of test pieces on the table from the start of the evening to the end each time.

So, I got a shot of the classroom this evening;

The "dark" 4 bays are on the left, the "light" ones are on the right.

 

The evening's task was to produce a T fillet like this;

This was the one the tutor did, he then flipped it and did the same weld but "weaving" to show the difference;

1st half was going "two steps forward, one step back", second half was drawing circles although TBH you can't really tell.

I bashed out about 5 of these to try without weaving (Vince taught me to weave and I do it on autopilot), my main problem is moving at a consistent speed but I got there in the end;

I mean, none of them are going to break in a hurry so I'm not too worried.

 

H was doing the same and got pretty good;

 

This was her best-of-the-evening which was a visible improvement on the first of the evening;

 

I was tasked with moving on to the cube - not sure it's any harder to weld but it is a test of your ability to tack something up - the reference cube is referred to as the "Michael Jackson" as it's really really bad:

Story is an apprentice got impatient and decided he could run before he could walk, and this masterpiece was the result! Perhaps most impressive is how it manages to contain almost every welding mistake simultaneously every angle you look at it from you see a different way it's all gone Pete Tong.

 

My cube is currently cooling off so no piccy, but it's at least 50% better than the reference one if I do say so myself

 

 

[Badger110]

Has he gone yet?

What time is he back and when will he post some pics

[FridgeFreezer]

Bad news - it's half term!

[landroversforever]

 

[Badger110]

7 hours ago, FridgeFreezer said:

Bad news - it's half term!

Ffs...

[FridgeFreezer]

And we're back - and they've got lights in all the bays now so everyone could see what they're doing!

This week was the final week of MIG and was basically doing a few more practice pieces - for most people that was making the cube (clamping, tacking up, prolonged welding with an ever warmer glove ) but as I'd already made a cube it was on to some other test/practice pieces to work on torch control;

Keeping the height and angle consistent throughout this was a decent little teaser - went a bit high in the middle.

This sums up most of my evening - there's a big box of metal ready to practice so I banged out a load of practice pieces!

Clockwise from top left - an edge joint / seam, tricky to keep the torch steady hovering above it. Then inside corners, again trying to keep going and consistent while the angle changes, then the circle - this went far better than I expected but definitely tests you, continually rotating the torch & keeping it on target.

I also welded the outside of the angle pieces later as a bit more practice, keeping steady & neat round the corner is the tricky part.

So, as I'd piled up a load of test pieces by now the tutor put me on to a new thing - spray transfer, AKA "this one goes up to 11"

So, big bit of plate and big lump of bar, meet ~200amps...

Apart from getting a very hot glove, I discovered that the torch was a bit clogged and the gas could've been wound up a bit, hence the textbook porosity

So, clean torch, gas up to 11, try again;

I don't think it'll fall apart anytime soon

 

Meanwhile H had been turning out more practice pieces and then moved on to the cube:

 

 

Anyway - next week is TIG

[Badger110]

Nice work!

Do you use higher amps for thicker material?

 

What does the porosity mean and why does it do it with lower gas pressure?

[Cynic-al]

I think it's fair to say you've nailed that one. Now I want to see you achieve the same quality whilst lying upside down under a land rover with mud falling in your face, everything rusty, covered in oil and next to the fuel pipe  

[Maverik]

10 hours ago, Badger110 said:

Nice work!

Do you use higher amps for thicker material?

 

What does the porosity mean and why does it do it with lower gas pressure?

Porosity is a result of lack of gas shroud over the weld pool protecting it, so the molten metal oxidises and produces slags which is when you get the porosity areas.

[FridgeFreezer]

14 hours ago, Badger110 said:

Nice work!

Do you use higher amps for thicker material?

What does the porosity mean and why does it do it with lower gas pressure?

Yes, there's a general guide for amps-per-mm although a lot of machines (the college ones included) set a voltage and then tell you after the weld how many amps you got... but more voltage leads to more amps. Whatever... you turn it up for thicker material and adjust wire speed until it sounds right / produces a nice weld.

What's quite surprising is that ALL the work up to this point has been at 17.6v / 4.8 somethings (m/min?) wire speed / 9L/min gas flow on the machines and you just adjust your speed of travel to suit the material. We've been welding ~2mm to ~6mm with the same settings.

Porosity is those bits that look like a Wispa bar and it's lack of shielding gas leading to oxidisation of the molten metal.

I hadn't checked the torch but it had a lot of cack in the end, just cleaning it might've been enough but I turned the gas up a twitch too just for safety.

[discomikey]

Looking good. Looking forward to see the TIG practise.

 

I was once told the phrase "Mig is easy to learn, but hard to master, TIG is hard to learn, but easier to master."

 

In my experience this is definitely the case. TIG just sort of clicks after a while. Feeding wire is important.. practise running wire through your hands when youre not welding so that it becomes second nature when you are.. Otherwise try and think about feeding rod through your hand when youre already concentrating 100% on the puddle, torch etc 🤣

[FridgeFreezer]

Very remiss of me, didn't post last week's efforts so here we go...

This is the box of discarded test pieces, gives you an idea of what the course goes through!

 

Anyway, last week was the first TIG session, so we had ~45mins of chat about what TIG is and how it's different, how the welder works (polarity, HF start, gas, tungstens, filler, etc.) and then the tutor showed us an autogenous weld (no filler rod) and a heterogenous weld (with filler rod).

Wwe're just on ~50x100 lumps of ~2mm mild steel plate here again, the welders are set to basic 1-touch DC, no foot pedal.

1st test was to go away and see if we could get a puddle formed and walk it across the piece without dipping the tungsten which challenged some more than others but we got that bit done reasonably OK (I still can't go in a straight line!) so the rest of the time was spent trying to add filler rod without touching the tip and producing a reasonable looking bead, which we both sort of managed but aren't going to win any prizes for

Here you can see H about to run a weld;

Test pieces visible on the bench, literally just running beads across to get the feel of it.

Insert light sabre noises here

The evening's efforts - I only glanced the tungsten with the filler a couple of times in the evening, H managed a totally clean run, others were wearing a path to the bench grinder but of course this is the first ~30 minutes of TIG welding most have ever done so it's all good.

General consensus was that everyone liked it - it's trickier to get the hang of and a lot slower than MIG but a lot cleaner & more controlled. Also the torches being quite chunky makes it a bit of a challenge to get comfy - all the college welders are light industrial sort of size (200A+ 3-phase) rather than hobby so they have larger torches for both MIG and TIG.

I suspect tomorrow night will be mostly a load of practising, maybe joining some bits together.

Tutor says if people make decent progress we might do some ali in the last 2 weeks - I'm crossing my fingers!

[Badger110]

Looking good.

So how will the Aluminium make a difference to what you do with Steel?

[Ed Poore]

My limited experience with TIG on Ali was predominantly about heat management. It took quite a lot of juice to get the puddle to form but then it could run away from you quite quickly, but this was on a test bead on some quite chunk 8mm ali which was pushing my TIG hard.

[FridgeFreezer]

1 minute ago, Badger110 said:

So how will the Aluminium make a difference to what you do with Steel?

I'll let you know if & when we get to it!

From what I understand through extensive YouTubing there's more setup with Ali - it's AC, you've got +/- balance (AKA cleaning) to worry about, and it doesn't change colour when it melts.

Also from what I've seen, there's some old folklore that's less relevant these days - balling the tungsten, using different flavours of tungsten, etc. that don't matter if you have an inverter welder that can control frequency.

[Maverik]

On 3/10/2020 at 9:42 PM, Ed Poore said:

My limited experience with TIG on Ali was predominantly about heat management. It took quite a lot of juice to get the puddle to form but then it could run away from you quite quickly, but this was on a test bead on some quite chunk 8mm ali which was pushing my TIG hard.

My few attempts at playing with tig on Alu was that using a big backing heat sink can be the difference between blowing the piece away and getting a decent joint the thinner the alu the more important. Maybe for an expert Tig welder they can control the weld pool better but for novice, heat sinks all the way for me.

[Cynic-al]

For going straight I found turning the work at an angle made it easier, so your following the arc your arm takes from your elbow. 

Be good to hear some tips. This is my second go with my tig since I got it. Not happy with it, it's plenty strong enough but I haven't got the technique yet. I think I just need to do straight runs for a while to try get the hang. My father in law is a welder on pressure pipes so is going to give me some tuition next time I see him, which will probably be Christmas.  I'm left handed but have been holding the torch in my right hand, not sure if that's the best way, might try it the other way.

I have done some aluminium and there is more to setting the machine but the technique is about the same. You have to back off the power more once you've got a puddle so I guess a foot pedal makes it easier than using the button. You have to use a different tungsten, white I think, and set the AC % to get the cleaning which depends on the grade of material and effects the strength, and you can adjust the width of of the pool, and it's harder to do on hot material for whatever reason. I need professional help... in more ways than one 

Edited March 13, 2020 by Cynic-al

[FridgeFreezer]

So, scores on the doors for TIG week 2; more practice (much like MIG week 2) and some joints:

 

One drawback is their stock of rods is all ~1mm which is quite hard to handle/feed and needs miles of rod to fill even a short joint, tutor is trying to get some thicker stuff for next time. Still, it's coming along, I gradually got some sort of consistency even if it's not winning any internet welding beauty contests!

Oh yeah, they'd changed gas bottles over and gotten air in the lines so there was a lot of random porosity going on in occasional bursts - tutor thinks there's maybe a leak that's let the air in.

This is the total evening's output from me:

Starting bottom left and working up basically - you can see it gets less awful as you go.

This was my least worst lap joint, I think:

 

And probably my least worst fillet:

 

 

Hoping they stay open for the last 2 weeks, it'd be a real bummer if they paused or cancelled it at this stage!

[discomikey]

Getting there, looking good. Hood time is the real thing here. Out of interest are you also practising at home? 

[FridgeFreezer]

23 minutes ago, discomikey said:

Getting there, looking good. Hood time is the real thing here. Out of interest are you also practising at home? 

So far I've done a few small bits but the bench is so covered in sh*** from working on the 109 that I've not really had the space or time to do any. I did TIG two nuts onto a plate on Friday, so there's that

 

[Ed Poore]

Has the instructor critiqued your welds? They look a little "rough" and I'm wondering if it's a bit cold. Ignore the ****ty mig run on these but hopefully you can see a difference. These were a sod because of all the cleanup I had to do, was a favour to an ex-mate and thought I'd use the occasion to practice my tig.

[Badger110]

Is there a benefit to using Tig on steel over Mig?