First Tig weld...

[Davek0974]

Done a fair bit of Mig, just bought myself an R-Tech Tig161 AC/DC unit, thought I'd teach myself Tig

Have read through the help guide here and also trawled the 'net etc, looks like I need to start on something like 3mm steel, running stringers and beads?

Do these settings look ok for starters....

1.6mm Red electrode
5-6mm stick-out
no7 shield cup
6l/min Argon
5s post flow
1.5s slope down
90A base current

Any other suggestions?

thanks

 

[Wallace]

For the post flow I watch the tungsten colour as it cools and trim it up/down as necessary so there is no discolouration. What size torch do you have and are you using a pedal?

 

[Davek0974]

The torch is sold as a WP26 and yes I do have the pedal too.

 

[Wallace]

You should be good to go with those settings and trim as necessary. There's a lot to take in with Tig at first but you soon get used to it.

 

[PSweeney]

add some slope up, should give you time to position the arc and get the rod in position ready to start dipping (or use the pedal to establish)

 

[langy]

Try 4-4.5lpm instead of 6, it will save a lot of gas and be fine

 

[Davek0974]

Try 4-4.5lpm instead of 6, it will save a lot of gas and be fine

Ok I'll try that, hopefully get some time this weekend.

What would symptoms be of too little gas?

 

[Davek0974]

Ok, time for some **** taking

Finally managed to get some play time tonight,

3mm steel, 90A, 5lpm
Autogenous (sp) beads....

Beads with filler rod, too slow at front?

The back, lots of penetration?

Then I thought, what the heck, and tried a fillet, 110A

I tack welded the ends first, this worked beautifully, then tried a run but found the rod favoured one side or the other, so I cheated and went over the top, this is the result above. Whether or not it's the done thing, I was most impressed at how easy it was to reflow the mess, add a bit more get a possibly usable result?

Things I've learnt...
The torch seems awkward to hold and move, I tended to use my wrist than slide along?
It puts a massive amount of heat down, not sure what I was expecting but damn hot!
There's lots going on, kept forgetting to feed the rod and ended up with a red hot glove

Considering it's my first time ever with tig, what you reckon?

I found it much more enjoyable than Mig and that's fun, being able to see what's going on was good too, watching the metal pool up and the rod flowing in is good. No spatter, much slower, time to think, excellent fun.

So suggestions please, obviously need to practice beads while moving but what's a good thing to do???


Oh, and I only dipped the tip once

 

[hotrodder]

Arc length, arc length, arc length... http://www.mig-welding.co.uk/forum/threads/arc-length.7862/ Covered in the TIG tutorial too. It's about the most important thing to nail

 

[Maker]

The biggest problems I had where too shallow push angle, so the heat reflected up and balled up the filler rod, and (still sometimes a problem) not feeding the filler, as you said, and getting a hot glove.

 

[Davek0974]

Arc length, arc length, arc length... http://www.mig-welding.co.uk/forum/threads/arc-length.7862/ Covered in the TIG tutorial too. It's about the most important thing to nail

Yes, that thread nails it - much too long an arc, I was at about 4-5mm when it seems i need about 2mm. Will be going in closer tonight hopefully, I'll leave the current set the same, don't want to change too many things at once.

I've also realised why the lower welds were all worse than the upper welds on my strip. I was running the upper weld first so the metal was cold, being a small strip it heated up and when I ran the lower welds it was already pre-heated so the welds were all suffering from being too hot as I didn't realise to move faster or use less power. I think that's the reason anyway, I did six pairs of welds along the strip, the tops were all better than the bottoms.

 

[BrokenBiker]

The biggest problems I had where too shallow push angle, so the heat reflected up and balled up the filler rod, and (still sometimes a problem) not feeding the filler, as you said, and getting a hot glove.

when i was learning i used to soak a torn up t shirt in water, wrong it out a bit and wrap it around little finger of torch hand. Now i have a tig finger which works better but both keep your glove cool

 

[Davek0974]

Do you wear gloves on both hands, neither hand, or one of those tig-finger things I've seen to let the torch hand slide???

Also what do you put on the non-torch arm to stop UV burn?

 

[langy]

Sensible to use a glove on both hands, I've sold lots of the Tig fingers over the years but rarely use one myself, best to wear sleeves, you only get one skin.
My advice to you is to forget all the gimmicks etc and just learn to tig weld the basic way, you can add tips & tricks once you have mastered the basic system

 

[Davek0974]

Ok, shorter arc, used the pedal too...

Tack welds...

Using the pedal helped a bit, to keep it simple I just set the max power at my limit and used it to provide slope etc.

Going to cut some metal up tomorrow so I can have a longer go at it.

 

[Davek0974]

Ok some more pics, these scraps are all about 5"x3" for scale, I've numbered all the runs, started at number 1.
All beads done with pedal limited to 90A, gas at 5Lpm, metal is all 3mm bright, laps were at 100A.

1- autogenous bead
7- bead with filler
8- bead with filler

2- longer autogenous bead

10- longer bead with filler

Butt tacks

14- autogenous butt weld, porosity due to contamination?
15- butt weld with filler rod

Prep for lap joints

12- autogenous lap weld

13- lap with filler, sleeve caught on bench so stopped short

15- bit more lap with filler

I think there are signs of progress? It's very hard not having someone watching to say stop, try this, do it this way - you never know if what you do is good or bad.

The few with porosity seem to have something in or on them, the arc flared up and the result was a hole. The metal was all scotch-brighted first, maybe I missed a bit?

 

[hotrodder]

Yeah, loadsa progress. Much better!

14- autogenous butt weld, porosity due to contamination?

Maybe but autogenous carbon steel often doesn't work well no matter how OCD the cleaning is. Mild steel TIG filler wire contains various deoxidising agents for this reason. With the common flavours of stainless (3xx series) that are more associated with autogenous welding the austenitic microstructure can absorb stuff that causes porosity in (the mostly ferrite) mild steel. Aluminium doesn't work so well autogenously with TIG either albeit for different reasons... it's prone to solidification (hot) cracking if the weldwool isn't reinforced and/or diluted with filler wire

While you can't get stuff too clean for welding it's overdone a lot of the time. Best thing for mill scale/mild steel IMO is one of those clean n strip poly discs, scotchbrite pads by hand will remove light surface rust but won't touch harder millscale and a wire brush in a drill tends to polish any scale instead of removing it

Might seem counter intuitive, especially at the minute but for butt welding 3mm you really need a root gap between the pieces http://www.mig-welding.co.uk/tig-butt-weld.htm otherwise it's not really much different from running beads on plate

 

[Davek0974]

Thanks.

Interesting stuff re aluminium etc.

The sheet I have is bright steel, no mill scale at all, that's why I just gave it a bit of a scrub. If I was using black plate I would definitely have used a flap wheel etc on it.

Will try the butt with a gap tomorrow, as per the tutorial.

 

[Maker]

Number 15 looks like you've wandered off of the line, try turning down the shade of your mask, or better yet, getting better (brighter) lighting around your bench, or do this, just so you can see exactly where your going.

 

[Davek0974]

Some more, first off my panel settings, these were for trigger start, when I fitted the foot pedal I set up-slope and down-slope to zero...

Then I set a butt weld with gap, half the thickness of the plate and tacked the ends with filler..

Next I tried welding the butt joint with filler,
Start to point A= too little filler or too slow?
At point B I over-run the weld pool and went back over.

Then I tried a fillet weld at 45 deg slant so welding into the bottom of the V. As it was now off the bench I found steadying my hand harder.

Finished up with a straight bead again,

Hopefully there is some progress somewhere? I'm not even sure of the correct seating position, this is rarely shown on YouTube videos, they sort of just get straight on with it, plus their torches all seem smaller and more hand-friendly than mine but that's likely just inexperience.