Practice makes perfect I'm told...

[AdHil]

Good evening all,

A long time back I came here in search of advice when buying a MIG machine. I decided to go for an ESAB C171 as I already owned an ESAB Buddy 160 that I used for MMA welding a few times and liked the quality of it. I have been having great success with my MIG welding and realised that now owning an argon regulator and having a BOC account meant I was only a bottle of Pureshield argon away from starting my TIG adventure! Exciting times.

I did a spot of reading here, and watched the tutorials and decided to have a bash. Now, there are a few small flaws in my setup. I don't own a bench grinder (yet) so I am using a 120 grit flap disc on a 4 1/2" grinder to sharpen my tungstens (something that I found myself doing rather frequently at first!) And my bench height/seating setup isn't ideal.. but apart from that I think I have the bases covered.

I have had maybe 3 or 4 sessions at it now and seem to be progressing, but I would like some criticism/feedback to make sure I'm getting things right. Below are a couple of welds on 1.5mm 40x40 mild steel box, done with a 1.6mm tungsten at approx 40 amps.

I know my beads aren't very stright/neat and I hope a steadier hand will come with practice but is there anything glaringly wrong with them? Is the first undefiled a bit? And should the heat discolouration have spread so far on the second? I will admit the second weld did involve a touch of weaving... but I have since read that this needs knocked on the head! Oops...

I went out for another play this evening with some much heavier material and produced these with a 2.4 mm tungsten at nearly 100 amps.

The weld on the right was several individual spots as I was just getting used to how the heavier material melted, then the weld on the left was done in one go. There was full penetration through the box but I am wondering if it would be normal to try and create such a heavy TIG weld in one pass? It did take a lot of filler and holding the torch in the same spot for a while?

I plan to gradually add any annoyingly simple questions I come up with to this thread and hope that one of you can help teach me!

Cheers!

 

[Richard.]

Good evening all,

A long time back I came here in search of advice when buying a MIG machine. I decided to go for an ESAB C171 as I already owned an ESAB Buddy 160 that I used for MMA welding a few times and liked the quality of it. I have been having great success with my MIG welding and realised that now owning an argon regulator and having a BOC account meant I was only a bottle of Pureshield argon away from starting my TIG adventure! Exciting times.

I did a spot of reading here, and watched the tutorials and decided to have a bash. Now, there are a few small flaws in my setup. I don't own a bench grinder (yet) so I am using a 120 grit flap disc on a 4 1/2" grinder to sharpen my tungstens (something that I found myself doing rather frequently at first!) And my bench height/seating setup isn't ideal.. but apart from that I think I have the bases covered.

I have had maybe 3 or 4 sessions at it now and seem to be progressing, but I would like some criticism/feedback to make sure I'm getting things right. Below are a couple of welds on 1.5mm 40x40 mild steel box, done with a 1.6mm tungsten at approx 40 amps.

View attachment 70813

View attachment 70814

I know my beads aren't very stright/neat and I hope a steadier hand will come with practice but is there anything glaringly wrong with them? Is the first undefiled a bit? And should the heat discolouration have spread so far on the second? I will admit the second weld did involve a touch of weaving... but I have since read that this needs knocked on the head! Oops...

I went out for another play this evening with some much heavier material and produced these with a 2.4 mm tungsten at nearly 100 amps.

View attachment 70815
The weld on the right was several individual spots as I was just getting used to how the heavier material melted, then the weld on the left was done in one go. There was full penetration through the box but I am wondering if it would be normal to try and create such a heavy TIG weld in one pass? It did take a lot of filler and holding the torch in the same spot for a while?

I plan to gradually add any annoyingly simple questions I come up with to this thread and hope that one of you can help teach me!

Cheers!

Nothing wrong with those
You've got the important stuff well under control regarding arc length, torch angle, filling consistently . They look pretty straight to me also.

 

[Willl]

I will admit the second weld did involve a touch of weaving... but I have since read that this needs knocked on the head! Oops...

What exactly is wrong with weaving?

 

[Richard.]

What exactly is wrong with weaving?

In certain application it is acceptable. Ie pipe joints, some processes for V up but in general on a joint in the flat position it's only going to make things worse.
From a non technical point of view particularly with tig it's adding high amounts of heat input into the joint. This from a more technical point of view makes the grains in the microstructure big (grain growth I believe is the term) large grains makes for low mechanical properties from a toughness point of view. Now the oppersite to this would be putting in a very very fast cold run. Equally as bad for the oppersite reasons extreamly fine grain structure and high hardness (makes a brittle joint) not so common with tig as it's a high heat input process naturally but very easy to achieve this with mig and mma.

 

[Willl]

That's good to know, thanks for the explanation. I did engineering at college, so I have (had) a fair understanding of metallurgy and the crystal formations of austenite, cementite, pearlite etc. When finding the right travel speed/heat input Into the workpiece, is the some sort of formula or rule for certain materials to get you roughly into the right area or is it just a trial and error on the day from practice and experience with the material? Thanks.
Apologies to Mr Adhil for going OT!

 

[Richard.]

Well when it's critical a heat input value will be stated on the weld procedure. This will be generated by your conditions which in turn will have an effect on the notch toughness values created.
There is a simple formular for working out heat input.
Amps x volts / (travel mm/sec x 1000) = j/mm.
Now you need to multiply that by the process efficiency factor.
.6 is tig
.8 is mma and GMAW.
For sub arc you don't need to do it as it's an efficiency factor of 1.

 

[Willl]

That's exactly what I was after, thanks Richard.