TIG Penetration

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Hello, I'm a hobbyist learning how to TIG and have a question about penetration.Hardware:Lincoln Invertec V155-S - Does not support a foot pedal or torch AMP control (neither would be useful anyway due to nerve damage)Torch 17V - Manual gas controlWired for 120 on a 20 AMP circuit and plugged directly into a 20 AMP GFCI outlet100% Argon GasGround directly to work pieceMaterial:Unspecified mild steel sheetThickness = .1201/16th ERS80-D2 filler1/16th 2% Thoriated TungstenPreparation:Edges to be welded have mill scale ground off using a medium angle grinder wheelWeld surface then smoothed using a 120 grit flap discFinished with an acetone wipedownTunsten ground with a medium bench grinder wheelTunsten tip polished with a 240 grit Dremel discAll Tunsten sharpening is done "with the grain"Now, since I'm new to this and learned everything I know from YouTube videos by welddotcom and weldingtipsandtricks, I don't really know what "good penetration" means, but I'm pretty sure I'm only getting it about 30% of the time...My long term goal is to primarily .049 thick 4130 for recumbent trike frames.Attached are some sample pictures from my first project of both sides of two weld areas. Basically it is a big steel box that I plan to use for stripping paint off of cut up bike frames.Thanks for any feedback and feel free to ask and questions not answered above.BillTungsten TipWeld Sample #1Weld Sample #2
Reply:Weird... the following lines are important but did not wrap in the post so here they are again...Now, since I'm new to this and learned everything I know from YouTube videos by welddotcom and weldingtipsandtricks, I don't really know what "good penetration" means, but I'm pretty sure I'm only getting it about 30% of the time...My long term goal is to primarily .049 thick 4130 for recumbent trike frames.Attached are some sample pictures from my first project of both sides of two weld areas. Basically it is a big steel box that I plan to use for stripping paint off of cut up bike frames.
Reply:Your picts are too large. That's why the text got cut off. You need to resize your picts 1st.You don't list how many amps you are running. I can't tell from the 3nd pict of the back of the weld where it says "lens", if I am seeing full penetration or just discoloring. You should have a distinct sign that you got complete penetration on the back side. You can see some of this on the right of the 1st pict of the back of the weld, but you only got full penetration on one piece, not both, and you didn't get it over the whole length of the weld obviously.Also not sure why you put the flat on the tungsten. I usually run steel with a sharp point. The only time I'll blunt the tungsten is with alum on occasion. You'd be amazed at how rough a tungsten can be and still do an adequate job at your level of experience.Front side your  1st weld looks too cold and very inconsistent. 2nd weld looks a bit better, but still has major issues. Last pict the weld just right of the ruler looks fair. There are still inconsistencies, but it's the best of the lot by far. Having a working pedal will help greatly. I'm not quite sure how nerve damage affects you using the pedal. It's just like driving a car. If you can manipulate the accelerator to adjust your speed in the car, you can manipulate the pedal to control your amps. It's simply a eye foot coordination. You don't really need to feel the pedal, just have the same basic motor skills needed to maintain a consistent speed while driving up and down hills and around corners. you will need that control to do thin stuff like you want to.Last edited by DSW; 04-19-2013 at 08:31 PM..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by DSWYour picts are too large. That's why the text got cut off. You need to resize your picts 1st.You don't list how many amps you are running. I can't tell from the 3nd pict of the back of the weld where it says "lens", if I am seeing full penetration or just discoloring. You should have a distinct sign that you got complete penetration on the back side. You can see some of this on the right of the 1st pict of the back of the weld, but you only got full penetration on one piece, not both, and you didn't get it over the whole length of the weld obviously.Also not sure why you put the flat on the tungsten. I usually run steel with a sharp point. The only time I'll blunt the tungsten is with alum on occasion. You'd be amazed at how rough a tungsten can be and still do an adequate job at your level of experience.Front side your  1st weld looks too cold and very inconsistent. 2nd weld looks a bit better, but still has major issues. Last pict the weld just right of the ruler looks fair. There are still inconsistencies, but it's the best of the lot by far. Having a working pedal will help greatly. I'm not quite sure how nerve damage affects you using the pedal. It's just like driving a car. If you can manipulate the accelerator to adjust your speed in the car, you can manipulate the pedal to control your amps. It's simply a eye foot coordination. You don't really need to feel the pedal, just have the same basic motor skills needed to maintain a consistent speed while driving up and down hills and around corners. you will need that control to do thin stuff like you want to.
Reply:Your right I misread that the 1st time thru. I was thinking his joints were open outside corners where he was filling the "V" vs tight butted corners. I'll agree trying to get decent penetration on both will be difficult if that's the way he has the joint set up..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Figures I'd forget something... AMPs were ~95Pedal: I'm right handed/footed and have a spinal cord injury that prevents me from maintaining muscle on my right calf so I have muscle spasms if I press on a pedal for very long without modulating it. On anything other than an errand run, I rely on cruise control... literally. And actually right now I can only sit or stand up for about an hour each day because I'm recovering from back surgery from Jan 28th.Tungsten Tip: This seems to be one of those "experts never agree" issues. Personally I'm finding that for my welder/materials/technique a little blunt is working better than a sharp point, I seem to contaminate the tungsten much faster when it has a point.1st Back Pic Right Side: That is exactly the feedback that I was looking for, from all the videos that I have watched, it seems like none of them really talk much about the back side of the weld so I wanted to be sure that I understood what "good penetration" meant.The corner is effectively a T. I Placed the sides flat on top of the bottom of the box. The sides are similar in that the long sides butt up against the ends of short sides. I have only tacked the side corners, so I'll grind those as suggested and see how the next welds fare.Question: If this were a true T joint like in an I-beam, what should the top plate above the joint look like to confirm penetration?Thanks for the feedback and have a good weekend!Bill
Reply:Originally Posted by TradetekFigures I'd forget something... AMPs were ~95Pedal: I'm right handed/footed and have a spinal cord injury that prevents me from maintaining muscle on my right calf so I have muscle spasms if I press on a pedal for very long without modulating it. Bill
Reply:Originally Posted by Tradetek1st Back Pic Right Side: That is exactly the feedback that I was looking for, from all the videos that I have watched, it seems like none of them really talk much about the back side of the weld so I wanted to be sure that I understood what "good penetration" meant.The corner is effectively a T. I Placed the sides flat on top of the bottom of the box. The sides are similar in that the long sides butt up against the ends of short sides. I have only tacked the side corners, so I'll grind those as suggested and see how the next welds fare.Question: If this were a true T joint like in an I-beam, what should the top plate above the joint look like to confirm penetration?
Reply:This tungsten grind chart may help you some as well.
Reply:@weldwordie: Simple lack of coordination at the foot level. I can't dance either  I did look at the file you linked, but it appears to be an exploded parts diagram of a commercial pedal. Did you mean to link something different? There isn't any text explaining how it would integrate with a welder that does not have a plug for an external amp control.@dsw: Thanks for that very good explanation. I had been under the impression that "Fillet Weld" simply described the shape of the weld, not specific characteristics of fusion. From what you are saying it also sounds like that in similar situations, I should weld the inside corner vs the outside corner. Because this was my first "simple" project I figured that I'd get the best practice by first welding around the outside and then weld again from the inside, but I'm now seeing that at this material thickness, that probably was not realistic and that I need to just do one side in the future and make sure that the weld penetrates through the joint to get adhesion on the other side. What is the best edge design for doing fit-up and welds of round tubes?@vpw: If I am interpreting the chart correctly, it sounds like you are suggesting that I probably have had my electrode at to shallow of an angle to the workpiece and need to focus more on keeping the electrode close to a 90 degree angle.BTW, I am using a gas lens with a #8 cup, but my stick-out is only = to the inside diameter of the cup opening and am using a gas flow rate of 15 CFH. Additionally, I'm using the "lay the wire" these welds were all done using the "lay the wire" technique.ThanksBill
Reply:Originally Posted by TradetekPedal: I'm right handed/footed and have a spinal cord injury
Reply:Thanks Raul, I'm supposed to start PT up in June for this past surgery (note that this is my second back surgery in 5 years).On the comments about the "cold" welds, I had set the amps lower than "normal" at 95 versus the 110 - 120 that the thickness dictates because I was having problems with blowing holes through most practice pieces if I used the standard 1 amp per thousandths of thickness. But from the comments it sounds like if I'm going to continue to do this, I need to go slower or I need to increase my amps and probably keep going at the speed I am now...?
Reply:The question here is "am I getting good FUSION?" The welding operation produces fusion of metal. Penetration is achieved by proper engineering and joint configuration. I agree, you'd be better to weld a fillet on the inside, and only weld the outer edge so it can be ground seamless for cosmetic reasons. This is the same reason when welding heavy plate, they use V joint configurations, be it butt or fillet. You have to have room to get into the root, and space to deposit weld metal.Also, I'm not a TIG expert yet, but It looks to me like you are either moving too slow, or adding too much filler.Lincoln Idealarc 250Lincoln Weldanpower CC/CV engine driveLincoln LN-25 wire feederMiller Syncrowave 180 SDVarious oxy-fuel setups featuring Victor, Harris, and Prest-o-lite products
Reply:Originally Posted by Tradetek@vpw: If I am interpreting the chart correctly, it sounds like you are suggesting that I probably have had my electrode at to shallow of an angle to the workpiece and need to focus more on keeping the electrode close to a 90 degree angle.Bill
Reply:You'll get fine results in the 45-60 point angle range, try taking the tiniest amount of the point off, you'll be less likely to dip the point. If you leave the corner open you will guarantee full penetration, but you'll need to turn the amps down. The acetone cleaning is usually done first, before brushing or sanding, to avoid smearing oil and grease all over the piece, but your weld looks clean enough. From the ruler to the arrow on the second piece looks fine, you just need to develop some consistency. I like to make a 1/16" zig-zag motion when I use the lay wire technique (aka continuous feed), it helps make the edges of the weld wet out to the same width. Travel speed is the only way you have of adjusting the heat on the fly. If your weld isn't wetting out at first you'll need more amps,  once you get going you'll need to increase your travel speed to keep the width even.SqWave 200Millermatic 190Airco 200 ACHypertherm PM45Boice-Crane Band SawVictor O/A
Reply:Originally Posted by Tradetek@vpw: If I am interpreting the chart correctly, it sounds like you are suggesting that I probably have had my electrode at to shallow of an angle to the workpiece and need to focus more on keeping the electrode close to a 90 degree angle.Bill
Reply:Thanks everybody, lots of good info for me to pay attention to and based on the pic of tungsten tips that VPT posted, my tips typically are similar to the second from the top.
Reply:I prefer the second point from the bottom. Having the point perfectly clean is more important than exact shape, I find the effective amperage to be a bit lower with a slightly dirty point.I hope to one day weld 4130 bike tubing, but first I'm going to spend a few years on the thinnest material I can find until I can stack perfect dimes on .035".What are you going to use as a stripper in the tank?SqWave 200Millermatic 190Airco 200 ACHypertherm PM45Boice-Crane Band SawVictor O/A
Reply:Don't know that this has been mentioned yet as it is irrelevant from the penetration topic, but OP stated his ultimate goal was welding 4130. If that is what you hope to do, you may want to familiarize yourself with some sort of amperage control (there is a great thread on here somewhere where a guy made a pressure-sensitive torch mounted amptrol). 4130 is very difficult to weld "straight up"(no amp control) especially for someone without a lot of experience. It is very prone to cracking when it cools too quickly, which can be causes by too much heat and travel speed and by not tapering the amps slowly enough at the end of the weld, even a breeze through your work area. This is just my personal opinion, but I would not weld chromoly without amp control on anything that mattered. -Rgfab
Reply:You said a mouthfull RG! I wouldn't really want to weld up a lunchbox without amp control, but I guess I'm spoiled. There's no way I would spend money on bike tubes at this stage in my tigging, but recycled frames can be had for the asking, once you clean them up you have some quality material for next to nothing. Tradetek, I would strongly suggest a finger tip ampitrol, the sooner you start using it the better, another option is to use a foot control, but keep your foot moving like you're operating an old treadle sewing machine, natural pulse SqWave 200Millermatic 190Airco 200 ACHypertherm PM45Boice-Crane Band SawVictor O/A
Reply:A guy known as Graucho over at AtomicZombie.com who is a true artist at painting frames recommended CitriStrip. He says that it will chew through enamel and paint. I'm hoping he's right because I've tried acetone and a heat gun and neither got much, if anything off.AED Motorsports in Indy gave me about 10 feet of 4130 round tube scraps to practice on before I start trying to work on an actual frame. The owner said that he'll help with scraps because he really liked the idea of my project being that it is for my son who has autism.I also have a local welding supplier who does night-time classes for pro's working on their various certifications. The instructor said he has no problems with hobbyists signing up and since it is a work at your own pace class, he rotates through the group and gives one-on-one instruction. When I am able to sit/stand for the duration of one session, I plan to sign up to get some real instruction, but with the economy being what it is, I wanted to have at least some basic skills before I start paying $65 per session for the instruction.I've done a lot of research on using thin walled 4130 and tube less than .120 thick does not require pre or post heating. NASCAR specs agree with this, so I think it is reliable expert opinion.I'm going to build my first frame using .065 mild steel square tube, and then decide if my welds are good enough for me to move on to 4130. The nice thing is that here in Indy 4130 is cheap. If I buy a length it costs me $1 to $2 per foot depending on the diameter and thickness. I don't ever plan to use the proprietary alloys made by Columbus or Reynolds, their bike frame tube isn't really targeted at my applications, and is mainly double butted and not available in the lengths I'd need for a recumbent trike. Note that if I don't ever get good enough to do .049 4130, that I'll fall back to thicker 4130 and still get the better tube strength even if I can't shave the weight. I will still get some weight benefits by being to use smaller diameter tube though.I use freecycle.org to get free bikes. Have about a dozen now. All of them except one are some sort of hi-ten steel. I periodically put out a wanted post to my local freecycle group asking for broken bikes and get at least 1-2 bikes each time. I was getting ready to start racing mountain bikes before blowing the first disc in my back at age 22, so I know my way around a bike and it's amazing what people think is broken! I actually have donated a few bikes to others that simply needed their chains untangled.Anyhow, I realize that having amp control at the torch or foot is common and normally expected and I could have purchased a welder that supported them cheaper than the one I bought. But I wanted a quality machine and the Lincoln V155-S TIG Ready Pack has a lot higher quality accessories and hoses/cables than the other cheaper stuff, but the end result is that my only dynamic amp control is keeping the welder panel close enough that I can reach over and manually turn the amp knob down to 0 when I'm ready to finish a run, but I don't plan to try to start mastering that until I have consistent control over the bead.If someone has a pointer to a thread that discusses how to retro fit a torch for a torch amptrol when the welder itself does not support any kind of amptrol, I'd be interested in reading it, but I won't be taking apart the welder and modifying it's internals, period. At the end of each weld run, the welder is designed to make a snap arc disconnect quickly with a twist of the wrist and then I keep the orifice over the weld area for post flow gas coverage. That being said, I am thinking of making a dead-man foot switch to kill the welder at the end of the run so that I don't have gas turbulence at the end of the weld while I'm trying to get post flow coverage.Since the trikes are for me and my autistic son, my goal is simply to have welds that are strong. I don't much care if they are pretty, just strong.I will also probably set my tube notcher in the box I'm currently building to contain the cutting oil, and possibly allow me to reclaim and reuse it.
Reply:I am probably one of the biggest advocates of lift/scratch start welding or any tig welding with no amp control. I still scratch start tig on stainless with a miller thunderbolt on occasion. I learned how to do it that way when I was just a little kid on .048 s/s.The problem isn't with breaking the arc and maintaining shielding gas coverage or "pecker tracking" the arc as you break it away. Chromoly doesn't have the same properties as mild steel and therefore it doesn't weld the same. The point of having the amp control with 4130 IS to make structurally sound welds, not pretty ones. You stated you simply wish to make "safe" trikes and what I am telling you that it is a fact that chromoly WILL fail if not welded properly. The cooling process after welding needs to be dramatically slower than that of mild steel. 4130 is not an "easy" metal to weld and taking the ability to control heat input only further complicates it. I'm definitely not saying it can't be done (cuz it can); hell I won't even say it shouldn't be done because I don't scratch start enough 4130 to know for sure.  What I am saying is that if you start weldin it up and the welds crack or fail; you'll know why. The trikes you are talking about welding up may be fine, I'm not familiar with the weld locations or the stress they'll be placed under.I can appreciate you not wanting to modify the machine to accept a remote device, but IMO if welding 4130 was something you had planned to begin with; I would have done some more research into the process of it and bought a machine that suits your needs more accordingly. -RgfabLast edited by rgfab242; 04-21-2013 at 09:10 PM.
Reply:Thanks for the info RG, this is the first I've seen any comments like yours and I actually researched the thin walled 4130 tube welding requirements for a couple of months before I purchased my welder.Stainless is of course an optional alternative, and another is 1018 DOM. I had eliminated SS because of the backpurge requirements but I've seen some conflicting info as to whether it is required for non-food/chemical/liquid storage environments.Bill
Reply:For structural I would backpurge SS. I even backpurge aluminum when I want nice (helps it flow together better on the backside). Even 4130 can benefit from backpurge.
Reply:Where are you located TradeTek? I think I have a solution for you. Your setup is just fine for fitup and tacking, including fabrication of the fixtures and jigs. I am willing to work with you and your machine, and you are welcome to use one of my tigs to complete the bike once tacked.Personally I hate lift start, but has come in handy at times. One summer 3 years back my kid and I spent weekends repairing and modifying stainless steel vacuum test chambers with the customer's miller DC tig. All I can say is that we were drained. Breaking that arc so many times when over-penetrating, and leaving no gas shield was murder.4130 is one of my favorite alloys to weld.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.Gary, very generous offer, but I'm in Indy. Did move here from Murrieta though so we used to be nearby.I did do some corners today and using advice here the backsides did look better, but still inconsistent, and some of the runs penetrated, but formed what I'd describe as popcorn kernels on the inside. I was having a lot of problems keeping my hand steady today though so I only did a little as I kept contaminating my tungstens by dipping into the puddle. Chalk it up to one my more bad days...In the next couple of days I'm going to grind all the edges down and get them to the 45 degree fitups that were recommended and then go through it again.Some of the stuff I tried today were corners inside the box where I didn't have much if any fusion from the outside, and really had a tough time controlling the torch. Hoping that was just excess nerve tremors and not a general issue I'm going to struggle with.Also discovered that I really want a couple chunks of aluminum plate to put under my hand, or I might even get some of Jody's "TIG Fingers".Bill
Reply:I use one of those tig fingers.  Works great - can drag your hand right over the weld if you want.Dave J.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:A few of my customers have brought in projects that they designed the weld joints..After being yelled at a few times they figured out how to give me the correct or close to it weld preps........Unless you have very thin material in my mind there isn't much penetration with tig, so a weld prep is in order.  Typically I always like edged to edge for tanks and all other thicker materials to keep the same wall thickness at the joint..Or a gap that lets the weld project through as in pipe root weldsLast edited by B_C; 04-22-2013 at 06:32 PM.  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:That's the thing, the bike tubing is quite thin, with good heat control you should be fine welding it without pre/post heating. You absolutely want the closest fitup you can manage.Last edited by Brazin; 04-22-2013 at 07:49 PM.Reason: +1 for TIG FingerSqWave 200Millermatic 190Airco 200 ACHypertherm PM45Boice-Crane Band SawVictor O/A