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Shielding the Filler Rod while Tiggin'
Posted: Thu Jul 04, 2013 9:56 pm
by Tally Tig
I have watched Jody's vids over and over for the past year or more while I have been teaching myself scratch tig.
Since I have tried to mimic what he does I notice that he seems to remove the tip of the filler rod from the shield gas area between filler dips. This could be camera angle though so I am not certain.
I have read many articles on tig welding and many specifically say to keep the tip in the gas.
How important is it to keep the tip of the filler rod in the gas shield?
Re: Shielding the Filler Rod while Tiggin'
Posted: Thu Jul 04, 2013 10:32 pm
by TamJeff
Your shielding gas should well encompass the weld zone anyway. The only time it really doesn't, is when your torch angle is off, which it will be from time to time in certain situations. Typically, in such instances, you will naturally be adding filler in the right place anyway with regard to gas flow. Some situations require you to sneak a dip or a few in the back side or off side of travel direction when filling gaps or welding to metal that is corroded or extra thin or where the torch just won't fit any other way. Otherwise, the puddle itself would be dirty and adding filler is going to be a crap-shoot anyway.
Harder to put into words than in practice, but with some time on the torch, you will become aware of exactly where the gas is and where your filler normally goes. If you have a well formed puddle, it is getting plenty of shielding and then some.
I often drop filler in spontaneously when I come across some weird fill and build situations, like where I have blown a hole off to one side of a weld joint. I feather in the filler metal intermittently, at a fine line between a good bond and fill, or making the hole even bigger. Mostly while welding thick metal to thin, or poor fitting joints.
Finally, I usually end up dipping or feeding at the leading edge of the puddle. If the torch angle is off and you are getting the filler in an overshot of the arc stream, you're going to blow the end of your filler rod off, and half the time, at the expense of your shoe laces. I suppose there are some instances where the filler is still partly molten and you could contaminate it pulling it out of the shield gas, but then it seems your feed rate would be erratic and the gas on the rod would be the least of the problems. Once you get your timing right, this should be a non-issue.
Re: Shielding the Filler Rod while Tiggin'
Posted: Fri Jul 05, 2013 1:29 am
by Vince51
It's very important. Will it cause radiation and kill half a dozen? Maybe if your welding in a nuclear powerhouse. It really just introduces contaminants into the puddle. Different metals respond in different ways. Doesnt make it easier. If i have to take the wire out of the shield then I either stop or flip it. I always keep both ends clean just for that( hard with full piece of wire). Hardly ever take it out tho. Unless I need to poke the fitter with a hot wire.
Re: Shielding the Filler Rod while Tiggin'
Posted: Fri Jul 05, 2013 7:37 am
by Alexa
TamJeff wrote:Your shielding gas should well encompass the weld zone anyway. The only time it really doesn't, is when your torch angle is off, which it will be from time to time in certain situations. Typically, in such instances, you will naturally be adding filler in the right place anyway with regard to gas flow. Some situations require you to sneak a dip or a few in the back side or off side of travel direction when filling gaps or welding to metal that is corroded or extra thin or where the torch just won't fit any other way. Otherwise, the puddle itself would be dirty and adding filler is going to be a crap-shoot anyway.
Harder to put into words than in practice, but with some time on the torch, you will become aware of exactly where the gas is and where your filler normally goes. If you have a well formed puddle, it is getting plenty of shielding and then some.
I often drop filler in spontaneously when I come across some weird fill and build situations, like where I have blown a hole off to one side of a weld joint. I feather in the filler metal intermittently, at a fine line between a good bond and fill, or making the hole even bigger. Mostly while welding thick metal to thin, or poor fitting joints.
Finally, I usually end up dipping or feeding at the leading edge of the puddle. If the torch angle is off and you are getting the filler in an overshot of the arc stream, you're going to blow the end of your filler rod off, and half the time, at the expense of your shoe laces. I suppose there are some instances where the filler is still partly molten and you could contaminate it pulling it out of the shield gas, but then it seems your feed rate would be erratic and the gas on the rod would be the least of the problems. Once you get your timing right, this should be a non-issue.
=====
TamJeff.
Quite a concentrated and rewarding post.
If it would of been ten times longer, I would of dedicated the time to reading it.
Tanks.
Alexa
Re: Shielding the Filler Rod while Tiggin'
Posted: Fri Jul 05, 2013 1:54 pm
by Otto Nobedder
The simplest explanation for the "appearance" of pulling the wire from the gas shield, is that the gas hits the metal and flows out along the metal for a distance before much air-mixing occurs. The shielded area is broader then, than a "point-and-shoot" perspective from the torch would suggest.
As Jeff says, torch angle plays a part in this. We rarely are 90* on to the part, and usually have the tungsten, cup, and gas flow pointing toward the leading edge, which expands the gas coverage on the filler side quite a bit.
Steve S
Re: Shielding the Filler Rod while Tiggin'
Posted: Fri Jul 05, 2013 2:17 pm
by TamJeff
Alexa wrote:
Quite a concentrated and rewarding post.
If it would of been ten times longer, I would of dedicated the time to reading it.
Tanks.
Alexa
Well, there is multiple reasons to leave the rod in the gas, and with the internet, there is possibly a whole school of thought that says it shouldn't matter. But unless you're dobbing rod for washouts or even ending a pass that's on the verge of washing out, it's probably going to be in it with proper fill technique for most of the joint anyway. With aluminum on AC for instance, the rod is likely going to be subjected to cleaning on it's way in to the arc stream anyway.
Didn't mean to go off on a long post but a few scenarios occurred to me in the process, being I rarely think about such things day-to-day anymore really. For the most part, the rod ends up staying in the shielding, unless I have had too much coffee maybe.
Re: Shielding the Filler Rod while Tiggin'
Posted: Fri Jul 05, 2013 2:49 pm
by Otto Nobedder
It got me thinking as well, because it rarely occurs to me on a day-to-day basis, either.
I know immediately with my next dip if I've pulled the rod from the shield with aluminum or stainless, because of the "dirt" floating on the puddle. It's not obvious with mild steel, though. I'm not sure it's as critical with mild steel, since it's common to do open root without backpurge.
It seeems to me to be quite important for aluminum and stainless, for different reasons.
For aluminum, leaving the shielding will build a deep "crust" of oxides, which, when dipped in the puddle can contaminate the weld deeply (cleaning action works at the surface), and leave a brittle weld. (I have no metalurgical reference for this... just my personal take reinforced by anecdotes.)
For stainless, pulling the rod from the puddle seems to oxidize the alloying compounds (sugar the end of the rod). While these impurities seem to float to the top, rather than become included, it reduces the alloy content of the weld affecting strength, hardness, and corrosion resistance.
With mild steel, the rod seems to develop a very thin layer of scale, based on my examination, which I believe in an otherwise clean joint is adequately compensated for by the silicon content of the rod.
Much of this is specutalion based on experience rather than science, so I look forward to others' take on the subject.
Steve S
Re: Shielding the Filler Rod while Tiggin'
Posted: Fri Jul 05, 2013 8:01 pm
by krazziee
very good info
I would like to thank you all too .
Re: Shielding the Filler Rod while Tiggin'
Posted: Fri Jul 05, 2013 9:16 pm
by Tally Tig
I agree in thanking everyone for this info. As a newbie most of what has been said has never occurred to me yet. I never suspected a simple question I had would lead to this much good info.
I have yet to attempt aluminum but will soon as I have purchased an HF251D-1 unit just for that purpose.
My stainless welds are not what I want yet either as I get a gray color to my beads instead of that pretty salmon/straw color.
So my concern was gas coverage of the rod and this info has helped.
Re: Shielding the Filler Rod while Tiggin'
Posted: Sat Jul 06, 2013 4:03 pm
by Otto Nobedder
If you've watched Jody's stainless TIG videos, you'll see he's nowhere near 90* with his torch, he's closer to 45*. A close examination will show that he moves quickly. He's mastered "just enough heat, dip the rod, and move on". There's three main components to succeeding with this; practice, practice, and more practice.
I sometimes still get gray weld surfaces. This can mostly be ignored. If a wire-brush brings you right back to shiny, you've done no harm, it's just a lack of back-coverage of gas for the speed/heat you're putting in. If it's dull after the wire-brush, you're either using too much heat to begin with, or lingering too long, and you need to make adjustments. The straw-colored weld will come in time, and I'll bet even Jody doesn't get it EVERY time, because sometimes too many things stack up against you to get it perfect.
Steve S
Re: Shielding the Filler Rod while Tiggin'
Posted: Sun Jul 07, 2013 1:57 am
by Tally Tig
Otto Nobedder wrote:If you've watched Jody's stainless TIG videos, you'll see he's nowhere near 90* with his torch, he's closer to 45*. A close examination will show that he moves quickly. He's mastered "just enough heat, dip the rod, and move on". There's three main components to succeeding with this; practice, practice, and more practice.
I sometimes still get gray weld surfaces. This can mostly be ignored. If a wire-brush brings you right back to shiny, you've done no harm, it's just a lack of back-coverage of gas for the speed/heat you're putting in. If it's dull after the wire-brush, you're either using too much heat to begin with, or lingering too long, and you need to make adjustments. The straw-colored weld will come in time, and I'll bet even Jody doesn't get it EVERY time, because sometimes too many things stack up against you to get it perfect.
Steve S
Yes. A brushing with a stainless wire brush does bring mine to a shiny weld but it looks pretty much like a regular filler wire such as ER70-S2 filler would look.
I try my best to mimic what Jody does. His videos are the main reason I have had the success I have enjoyed so far.
Re: Shielding the Filler Rod while Tiggin'
Posted: Sun Jul 07, 2013 5:48 pm
by Otto Nobedder
Jody's videos, like any advice you read here, is a starting point. No two of us do it exactly the same. Don't be afraid to experiment with torch angle, motion, speed, stick-out, power level, and any other variable you can think of.
What Jody does works great for Jody. It might only work "good" for you, and you'll find what works best only through getting comfortable with experimenting. Every variable I mentioned above will make the puddle behave differently, and only by experimenting will you see the differences and begin to get a feel for what works best for you.
Once the weld is wire-brushed, it should be the same color as the base metal around it... The "straw" color goes away, too.
Steve S
Re: Shielding the Filler Rod while Tiggin'
Posted: Sun Jul 07, 2013 9:21 pm
by TamJeff
I've found in the last few years that I don't really have a signature torch process. Even something as subtle as changes in the weather can change it. For example, when it is hot weather, I tend to naturally keep the hot work further away. This changes perspective. Also, I will have fans blowing at me, requiring me to tighten up on the shielding. Enough of a difference to where it will appear different people welded the exact same parts at different times of the year. In Winter, even though I will be less effected by the heat, I may instead be trying to keep warm, holding my arms closer to my body or having heavier clothing make me change my stance.
Re: Shielding the Filler Rod while Tiggin'
Posted: Mon Jul 08, 2013 1:56 am
by Vince51
I know how you feel Jeff. My fab area caps look completely different from a hot tap on a steam line. Not enough k wool in the world to get comfortable. Seems I do my best looking work in tight quarters tho. Never could figure that out. Good reading here fellas. Thanks
Vince