[sausageroll]

Hi All,

Im new to tig welding (this is my fourth day). I have a 130amp scratch start inverter, with a pretty standard torch (I am set up as negative earth, as im told is correct). Im using mild steel mig wire for filler at the moment. Im using 1.6mm red tip tungstens, sharpened the correct way on a bench grinder.

Following the various tips on this site, im keeping the tip of the electrode 1-2mm from the puddle, and torch angle as close to vertical as I can get it.

I am using pure argon of course.

So my main question is, occasionally I get a big blob of filler on the end of the electrode. Is there a reason for this, or is it simply because I dipped the electrode into the filler by mistake? Is there a way to avoid this? If this happens, do I just grind the filler off back to a point and carry on?

Thanks for any help,

Pete.

[noddybrian]

Hi & welcome to the forum.

Mostly sounds right - but you were mis-informed on the polarity - Tig is conventionally done positive earth - electrode negative.

Torch angle as upright as allows vision of the puddle is a good guideline & should you progress to aluminum the practice will have helped - but on carbon steel while learning it's OK to use a shallower angle so you can see what your doing & if using an appropriate cup & gas flow should not give coverage issues.

I think part of the learning curve with Tig is keeping the electrode close enough to the puddle without dipping it - we've all done it - try not to worry what the exact distance is like your stated 1 > 2mm - just keep it as short as practical without repeatedly dipping the tungsten - again carbon steel will forgive a fair bit - just keep practicing & shorten the gap as your hand movement settles - use anything available to prop with will always help ( of course buying a Tig finger never hurt & will help the Guru maintain his lifestyle ! )

When adding the filler rod increasing the arc length momentarily helps - if your too close as the puddle takes the filler it will rise slightly - so contamination is more likely ( again - less of an issue with carbon steel )

Carbon steel also tends to have more contaminants than other materials - make sure you clean every bit of rust / mill scale / grease / anything else off the surface - a quick de-grease never hurts either - any of these things will react with the heat of the arc & spit at the tungsten - often contaminating it.

If you have just a small amount of base metal on the tungsten I would say as you have a bench grinder - put a fine wheel on one side & only sharpen clean tungsten on that but reserve the other side for removing the ball of contaminant first - don't use the same wheel as it will load up quickly & transfer the material back onto the tungsten - this is just good practice - you can get away with alot on the sort of work your doing - but going to stainless or aluminum it will show up - if it's a great big dollop completely covering the end I suggest as 1/16" Thoriated is cheap - just snap that bit off carefully & then re-sharpen.

Hope some of that helps & good luck with whatever your making.

[weldin mike 27]

Hey,

Seconded . Great info Brian.

Mick

[sausageroll]

Hi Brian,

Thanks a lot for your info, its nice to find a forum with good helpful people on it.

I mistyped my sentence about negative earth, I am in fact using positive earth, I just typed it wrong. Just out of interest, if I had it the wrong way round (negative earth) what would happen?

I have already ordered a Tig Finger .


I was also going to ask if you had any pearls of wisdom for starting the arc up... I find that if you fail on the first go, and the electrode sticks, then your nice shiny tip is ruined. Are there any really good tips for getting the arc going easier, or without damaging the electrode?


Thanks a lot, I will have another go and see how I get on.

Pete.

[Otto Nobedder]

Welcome, Pete!

If had your polarity wrong for TIG, you'd melt your tungsten into droplets (or splinter it, depending on alloy and quality) before you even established a puddle, at more than very low amps. That's why most stick-welding is electrode-positive, to "consume" the electrode and draw it into the puddle.

As for easy arc-starts with scratch-start, go to the plumbing or elecrical supply and buy a ground-bonding strap, a thin strip of copper. Spend the extra couple bucks for pure copper, not plated. Or if you have scraps of copper plumbing, smash it flat with a hammer, buff it clean, and use it the same way. Clamp it to the work right next to your weld, and scratch off of it, near the edge. It won't stick (unless you really ham-fist it), and will blow off any copper it picks up almost immediately so it won't contaminate your weld. Note: This is a great cheat for the hobbyist or home shop, but won't fly on most of the better jobs, and is a no-no on a weld test.

Steve S

[noddybrian]

I did wonder if the polarity was a typo - only time I did it by accident was on a long set of un-marked extension leads & I made nothing resembling a weld & balled the tungsten up within seconds.

Scratch start is not the easiest to learn although it's all I had originally - as Otto said a copper run on plate works if near an edge very well - it can be laid on a stop / start sometimes - but my only self taught "trick" which is probably going to get laughed at & is not conventional or at least I never saw anyone else do it - when I first was trying to scratch start on steel pipe somewhere awkward I rolled a very small ball of fine steel wool & placed it where I wanted to start - if your careful you can touch that & start the arc - it's so fine that it leaves almost trace on the tungsten ( this was way back & I had no one to ask advice - way before computers / Google & Utube ) - I don't do it anymore - but at the time I was learning as I went with a big old heavy torch I got hold of on an engine drive - I could start an arc OK where I could see well & get in a comfortable position - but had problems traveling around the back of restricted access pipe joints - obviously in the future if Tig suits your work maybe look out for something affordable with HF or at least lift start - even the most basic of inverters nowadays will do lift start.

I can't remember the tittle but Jody did an "old school" scratch start set up with a home made rectifier on a buzz box not that long ago - maybe worth searching it out - I'm sure there will some wisdom to be learned from it.

[Braehill]

I have to use an old ac/dc buzz box in the plant all the time, so scratch start is still the norm for me. It's still the norm for a lot more people in the field than most people would believe.

I've fould that this type of welding is always going to pick base metal on your tungsten. If I'm welding a 4" pipe and only have to start 4 times per pass, my tungsten barely shows this pick up. On the other hand, if I'm welding say an angle iron frame for something and have lots of starts,I'm constantly resharpening my tunsten. It's just the nature of this type of welding.

And then theres hanging off a ladder on the side of a stack that even a tig finger can't make comfortable, sometimes you can't find anything to brace on and you will touch your tungsten in the puddle or with the rod. It can't help but to pick up either the rod or the base metal if you touch it while welding or while starting.

The only "trick" I have is to put your torch close to your work and use the end of your rod to stike between it and the base metal like you were striking a stick match, much easier to do than to type out. I think Jody brings this up in the video with the old school welder.

Len

[sausageroll]

Hi Everyone,

I had seen the buzz box video, and I had seen the flicking the rod between the work and the tip. I havnt tried this yet, as im not too good at holding the torch really steady yet, il get there.

You say lift start, and most basic inverters have it... What is it? My inverter is basic, but its not *that* crap, id hope that it has this? Im guessing that ive never heard of this feature, my inverter does not have it.

Il have a go with the copper tomorrow, thanks a lot.


Pete.

[noddybrian]

Simplest way to tell - does your inverter just have an on / off switch & amp control - nothing else ? if there is a switch that shows stick / Tig then it has lift start - if it does you need the tungsten " stick out " the right length but all you do is touch the tungsten to the work momentarily - the machine will not put welding current on yet - now roll the torch to a shallower angle so it breaks the connection - at this point the machine senses the resistance change & powers the torch - it's fairly easy at higher amps with larger tungsten but slightly harder at low amps to maintain the arc initially - that's why you roll the torch on the cup rather than just pull back - it gives a steadier control - especially if your still learning.

Hope this helps and good luck practicing.

[sausageroll]

Hi Everyone,

So annoyingly my inverter does not have lift start. Il have to practace normal scratch starting then.

My Tig finger came today, but its not big enough to get over my gloves. I do have pretty heavy thick gloves, I would like to upgrade myself to some of those nice thin tig gloves at some point. I also have freakishly big hands which cant help.

What should I do, I want to use the finger but I dont want to forgo my glove because of it. Hmmm....


Pete.

[noddybrian]

Well at the moment your only real choice is to source some thinner gloves - if you're trying to Tig with regular welding gloves that you'd use for stick weld or cutting you will not have good dexterity & this makes the learning curve harder - I suggested a while ago that the Tig finger needed to be made in more than one size - I believe Otto put this forward to the Guru along with a suggestion for a better Tig glove - I've not heard of any progress on either to date - but we live in hope !

Unless your going to run an air cooled torch at very high amps continuously I suggest finding a thinner glove - even if it's not sold as a welding glove - over here they are hard to get but there are plenty of soft leather drivers gloves - often deer skin sold for lorry drivers while roping on loads etc - these work OK & are not expensive.

[Otto Nobedder]

Pete,

I have to agree with Brian. I TIG bare-handed when I can, and thin gloves the rest of the time. I even quit buying those $15+ "TIG" gloves. I find the cheapo bulk-pack goatskin work gloves the boss buys to be nearly perfect.

Steve S

[sausageroll]

What do you think? 3mm mild steel....

[Otto Nobedder]

Looks solid to me. I only see one small undercut, at what appears to be a start/stop about 1/3 down from the top, and that could be camera illusion/shadow. It appears you adjusted your heat or your speed at this point?

The heat-affected zone suggests you got good penetration, without overheating the metal.

The finished appearance is generally good as well, and will become more consistent with torch-time and patience.

Nice work!

Steve S