Problems with fillet joints

[JupiterComplex]

Hey everyone,

I want to learn how to weld for hobby purposes, so I bought myself a cheap TIG/Stick Inverter from ebay and all the equipment.

I tried some autogene and butt welds a couple of hourse, then adding filler rods. While butt welds seem to look somewhat okay, my fillet welds are still a mess.

I watched your tutorials and information in here, but won't get a good result.

So this is how I try to do fillet welds:

I lean the shroud on the two corners to get a good 45° angle, while the 1,6mm tungsten (grinded in right direction) is at a distance of aprox. 2mm to the corner. For that 2mm mild steel on the picture I tried 75A, traveling along the corner and feeding filler rod. But the bead just sticks to one of the pipes, there's no real connection between them...

And there are two other questions:

-At one picture you can see little cracks on the bead, what was wrong there?

- And can I still use tungsten, which touched the weld pool and has a bluish color, if regrinded correctly? Or will this automatically end up with bad beads?

So far, thanks for your help! -Marco

And sorry for my spell, english is not my native language.

 

[hotrodder]

Your arc length is too long... http://www.mig-welding.co.uk/forum/showthread.php?t=7862, also covered in the tutorials
The butt weld looks cold, again i'm gonna go with too long of an arc length from the heat discolouration... as the arc length increases the heat spreads out so instead of getting a small, focused weld pool everything gets too hot except for the weldpool if that makes sense.

Contaminated tungstens... if/when you make a proper mess and end up with a large blob of weld stuck to the end then better off cutting 'em back before regrinding. The one in the pic that's lightly contaminated, just resharpen- the discolouration is probably mostly light oxidation from the hot tungsten coming into contact with air

Are the cracks actually cracks or is it contamination/dirt? I'm thinking the later and i wouldn't worry about it too much at this stage of the learning process

 

[Drains]

A sharper angle on the tungsten should help focus the arc too. The top tungsten point isn't bad, but I'd make the point a wee bit longer than that. The used tungsten tip is way short, but that may be due to the touch-down.

Also, for that material (3mm thick?) I'd use a 2.4mm tungsten and a few more amps. Hot and quick is best!

 

[JupiterComplex]

Hey,

@hotrodder:

I'll try out a shorter arc distance next time! The cracks are "real" cracks on/in the bead, no dirt.

@Drains:

Have grinded the tungsten at a sharper angle. Hopefully it helps.

I welded 2mm mild steel. I also tried higher Amps (around 70-75, like you said), but my problem was, that I burned a hole in the material faster than I could see. So I'll stick to ~60A for now, till I get more practice.

 

[hotrodder]

Arc length and amperage are related in that the voltage goes up with arc length i.e. you put more heat into the work for a given amperage but in a bad way. Fix the arc length problems (easier said than done) and the edges won't be burning back so much/as uncontrollably.

They really don't look like cracks in the pic... Entire article's worth reading but have a look at figure 6c versus 6d here http://www.millerwelds.com/resources/articles/common-TIG-GTAW-welding-problems-visual-guide-graphic
If they are cracks the only thing i can think of would be shrinkage cracks from the combination of too hot (excessive arc length and slow speed) and too cold (not enough amps/incomplete fusion) but i'd expect cracks that follow the weld centre line in that case

 

[JupiterComplex]

Hey,

It's me again and I'll have to annoy you with another probem:

Whenever I try to weld butt joints, mitered joints etc... I often run into the problem, that the arc only focusses onto one of the pieces. So instead of melting both pieces together, its just one piece melting and due to the "too much" heat on this piece, it burns back or shrinkens.

Maybe its a problem with the grounding? Its always the piece with the ground clamped to it, that burns backs. I always try to cut the pieces, that they fit together tight, but due to my ordinary tools, there might be a gap of 0,5mm here and there.

If this problem appears, I can also hold my torch/arc to 90% on the groundless piece, but it won't help...

Any advices for me?

On the picture you can see, that I first had the ground clamp on the left part, which burned back instead of melting both pieces together, then the clamp was on the right part...

 

[Paul.]

It will certainly help if both parts are grounded, if you are working on a wooden bench just lay a piece of steel across the two parts to join them electrically while you get a tack on it, use the filler rod to bridge the joint to get the pool started as I have done in the tutorial http://www.mig-welding.co.uk/tig-butt-weld.htm. take note of the torch angle and the short arc gap.
However as you have traveled the length of the joint yet still missed one edge it looks to me as if you either can't see what you are doing properly, or haven't yet learned what to look for when welding.
Tig is a very precise process carried out at closer working distances than most people normally use, you may find some reading glasses will help, and make sure your helmet lenses are clean.

 

[Wozzaaah]

Looking at the left piece as you're viewing it I'd say Paul is bang on the money, you've not burnt the edge away, it looks like you've missed it completely!

 

[Drains]

As Paul says, get some tacks on the job!

 

[JupiterComplex]

Hehe you know what the problem was? Due to my cold working place, my welding helmet got foggy because of my breath. I thought this blurry view would be normal while welding, but then suddenly... big enlightenment.

Got some dish liquid on my helmet and everything is perfect. Never had the problem of missing the target, again.

Anyhow thanks for your help, you gave me some good tips and advices