Another TIG beginner

[Mark_M]

Hi all, I just bought the R-Tech 201 AC/DC Tig from Brad93, bought all the gear and started practicing. Brad encouraged me to post my experiences on the forum, so here I am.

Day 1, first mistake: no gas. I hadn't set the cylinder/regulator properly, I ruined the tip on 5 before I figured out what I was doing wrong... doh

After fixing that, I got this:

This was on 0.8mm stainless at about 20A. I knew it was very thin for a first go but just wanted something to go through the motions on and it was the only bit of metal I had that was already clean. I just wiped it with IPA before welding. Is that likely to be enough if there's no paint/grease/rust to start with?

Day 2 attempt was laying beads on 6mm stainless:

I'm guessing I had the torch too high. On the mirror stainless I could see a reflection of the tip, on this it wasn't so clear.

This was with 160A DC. these were the settings:

For steel, do I only need to change the amperage as I change thickness?



3, butt joint in 12mm mild steel. This was rusty as hell to start with so it took a fair bit of grinding back. I added a 4mm chamfer and space the plates slightly. It may be a bit difficult to tell from the photos but is this surface prep sufficient?



Welds:



Ignore the divot right at the end, I had a breaker trip, so gas, arc and lighting just cut off abruptly.
To me, these welds look better than the beads on stainless but clearly I need to work on my speed and feed.


With some effort, I broke the weld to check penetration:


Bugger all. The welds were well stuck, just only ~3mm deep. Do I just not have enough current for this thickness or am I doing something wrong?


4: 5mm mild steel, still the same settings:


The dull grey look again and I guess really overheated (it was glowing red). Is this the torch too high or something else? Much better penetration though.

I tried again on the same piece but this time concentrating on holding the torch lower and backing off on the pedal once the pool had been established:


That looks worse to me.

Any criticisms or suggestions welcome.

 

[Brad93]

They are good efforts mate, a lot better than when I first started. Gas shielding looks good, nice clean beads, heat built up too quick on the first bits of thin plate, on the thick plate i think you probably needed a few more amps when you started. I would start by practicing with the torch switch rather than the pedal and move on to that at a later date because using the switch teaches you greater puddle control using arc length, travel speed and filler deposition to chill the pool.

 

[Mark_M]

First project, welding a test rig from 2mm wall, 25mm square tube:




It was pretty eye opening trying a bunch of different joint types and angles all on one part. The welds ranged from ok (to my eye) down to terrible. Here's a selection:



In hind sight, I really should have ground the tubes to a better fit. I have no idea why I though it was a good idea to leave them so rough. I mostly managed to bridge the ~4mm gaps I had in places.

Here's the assembled rig:


One thing I noticed was that some of the welds quickly changed colour after the post gas flow turned off. So I extended the post flow out to 12s (I think it was still on 7s to start with) and that meant the last few welds were a bit more rainbow coloured. I assume that's a good thing?

You can just see ii in this pic, the end of these welds are a slightly different colour:

 

[Richard.]

Your coming on nicely but I have noticed in those last pics lots of weaving going on. No need for that just go straight lines keep your arc tight

 

[Brad93]

No need for more than 5-6 seconds of post flow on mild steel heat tint wont affect the properties anywhere enough to bother us mere mortals outside of aerospace, defence, etc etc.