Mig Welding that look like tig

I enjoy welding technique threads. I'm old and was taught with ox/acet. first and then with the old Lincoln tombstone AC machine. I think sometimes new weldor's are not taught enough about the basics and understanding what they are seeing in a puddle. As posted by a few welding engineer's these pretty welds would not x ray worth a dam. For beginers keep practicing basics and don't get caught up in the appearence game, a pretty weld is no guarantee a safe weld. All these technique posts always seem to show off bench welding, there is a big difference when you are welding out of an ideal position on a project that you don't have the luxury of a flat workbench and braced hands.

 

I use maybe four main, but different techniques. They all deliver an appearance similar to those you see in the video and some of the pics posted since.

The first is what you see in the video. Watch closely and you'll see that the torch is being swirled in a circular fashion, continually moving forward. I guess you could call it a helix or corkscrew path. It's a slower method that uses a lower rate of fill and spends time on the material to facilitate good penetration. It's great on that moderately heavy material you see in the video.

Another, some call stitch welding, is very much like a stack of coins in appearance. It's the triggered on/off/move/on/off/move pattern. It is very much like a good tack slightly overlapping the one beside it. I like this when I am working heavy sheetmetal that won't be ground after welding. Stuff like corner seams and joints in structural sheetmetal, 16 ga reinforcment plates, 1/8" floor plates where something might tie into the body, etc. I use the same method for sheetmetal, though it is usually ground back before bodywork.

My most used is another stack of coins and I got it from a couple of talented tig welders I know. I use it most on structural components like chassis tabs and brackets, spring perches, cage work, etc. It's much like the one above, but you never let off the trigger. Use higher heat and moderate fill rates. Hold the heat on one place, pushing the filler into the puddle (but not our the other side), as the puddle grows to width, snap forward 3/4 the diameter of the puddle, push the filler in until the puddle grows to size and overlaps back on the previous puddle, snap forward and repeat. The rhythm in this is very much the same as used in tig welding where you move the torch ahead, push the filler rod in, move the torch ahead, push the filler rod in. I get best results by counting in a rhythm; move, 1-2-3, move, 1-2-3. I don't dance, but I can count.


Lastly, when faced with a wider gap or maybe welding overhead, up the verticle, etc., where gravity is not my best friend, I use a half moon pattern. If you have a C shape and you are welding left to right, you trace the C, inching forward very slightly with each stroke. Heat settings are usually lower and fill rates are low. It allows the far side of the puddle to cool for a brief moment while you move up the other side, then you swoop back the other way, advancing the puddle in an almost Pac-Man way. This is very helpful where sheet is thinner, butt joints are not as tight as you would like or the metal is somewhat erroded, helping you avoid burn through and fall out that leaves even bigger gaps to fill.

Sometimes, though, it's not so important how it looks and the mig just does what it is supposed to do. Set the right wire speed and heat so that you can move forward at a steady pace, allowing proper penetration and build of the filler. You get a weld that looks like a machine did it in a seamless motion. This can be just as challenging as the pretty coins and is every bit as good a weld. Being human, it's our lack of consistency that betrays us. I've seen aluminum fuel cells welded by both man and machine. Either can look fantatstic. Either can run a constant bead or rhythmic coins. The best hand welded materials are the ones that make you wonder if they did it with a machine. Consistent. That is where practice pays off.

 

Heres a couple of mine i use the C method when MIG welding.






Justin

 

Thats some good information scottybaccus! Thanks for sharing.

Andy.

 

The experts on here crack me up. The parts being welded aren't ships, boilers, buildings, aircraft or spaceships. They are not 1/2" thick plate and most shown are brackets on frames. I know your all way over qualified for doing hotrod parts so why not bring it down a notch ? I have known many tradesman welders that worked at A.O. Smith back in the day. For kicks and giggles look at any sub-frame from any Camaro or Nova, and look at the welds done by pros. Most only have the weld on 1/2 the seam 1/2 the time. Guess what, 40 years later their still in one piece. What we're talking about here are parts that are being welded on a vehicle that averages less then 5000 miles a year. I uderstand where your coming from and shitty welds could kill you ( none of which posted are, maybe not optimal , but not shitty ) but I tend to think your a bit overkill for hotrod purposes. Just in case your wondering I do a continual bead and then grind and smooth. Just my $.002.

 

I am not going to speak to, or judge anyone's qualifications here. That is not my job.

Here's a little background on me. I am a professional welder, and have been my entire adult life. I have been welding since 1978.

My first professional welding gig was welding critical components on Los Angeles (688, 688 improved) Class nuclear submarines (specifically SSN-724, 725, 751, 752).

I am certified to weld just about everything, in every position, to levels beyond what most people here claim that they are qualified for. Any metal, any process, any position, any location.

I am even an experienced underwater welder, having worked out of Galveston Texas, on oil exploration and drilling rigs, as well as support equipment and vessels.

My welds can be found on the bedrock anchor-plates of http://en.wikipedia.org/wiki/One_Rincon_Hill, the tallest building in San Francisco.

I can and have welded everything from eyeglasses, to experimental aircraft components, rockets, to prototype super-cavitation torpedoes, and even stuff for the DoD, who's purpose was not known to me.

I took that fat stack of cash that I made at the shipyard and put myself through college, where I got a Masters Degree in Mechanical Engineering.

I have never had a weld fail destructive testing (or any other inspection), from certification test one, through now. 0.060”-6” Not ever, never.

Those of you who have judged Skoty's welds from a static image or the video are missing several things. From the pictures, you cannot see what was done to the metal to prepare it, for instance, beveling, fitment, etc., or the welder settings. The video does not show the puddle, as the brightness of the light over-peaks the CCD in the camera. All you see is glare, so there is no way any of you could have seen whether or not the puddle was allowed to cool. In short, you are speculating.

I know that coupons of this exact thickness of metal, and all of the common ones welded with this technique in Skoty's shop have been subjected to x-ray, non-destructive, and destructive testing, and all passed.

How do I know?

I prepped the metal, fit the pieces, shot the video, and inspected the welds.

I will put my welds (and Skoty's), and my unblemished welding history up against any of yours, any time. I'll even let you choose the metal, process, position and location.

 

That sums up the way it works for me!

 

Hi guys,this is my first reply ever. I serf these articles to gain some knowledge from you guys that have been doing this for a long time. I am just starting out in this hobby, only 4 years now. I have been ARC welding for years now, but I only just started MIG welding. I can say from a newwbie point of view, that gas is alot easier than flux core. My welds still look like crap, but I am more interested at this oint in penetration. I igure once I get really good with that, I can work on making pretty.

 

It is all about practice. You can never have enough practice. Be patient, it will all come in time. Don't let anyone discourage you!

 

I have a friend who builds very high-end bicycle frames (aluminum).
I've watched him weld a first pass to properly join the tubes and then go back and do the 'stack of dimes' look in a second pass for cosmetics only.
I asked about it and he said people just won't buy it if the weld does not have that certain look, but since his rep depends on his frames not breaking, he does the first pass to ensure durability. I take that as meaning that pretty welds aren't always the strongest.
He heat treats the frames afterwards.

 

AAHH! Alas some one who knows what the fuck he's talkin about! To start with no matter what you are welding to get the so called "perfect weld" everything (the metals you are joining) must be perfectly clean with no paint, oil, dirt, slag etc. second the heat range, proper gas, gas flow, wire, wire diameter, wire speed, tungsten, etc must be matched to the proper application. Pretty comes with experience as you learn to control you metal as you apply it in a proper manner. Just saying this guy is right on as I myself spent a good part of my working life as a 100% x-ray nuke pipe welder. The guy's who cared about pretty usually didn't last long, about three bad x-rays and they were gone...as we used to say, it takes "The eye's of an eagle and the hands of a skilled brain surgeon" of which I have none of now. Yes it is only a car frame but it needs to be done proper and safe....just my 2 cents worth.

 

Not picking on you Gimp but since you offered the challenge I accept.

For the metal I choose 5083 aluminum 5 millimeters thick.

Position will be flat, I know easy huh?

Location will be my shop in Slidell Louisiana

Process will be FSW (Friction Stir Welding)

Joint will be square butt, no gap, full penetration.

You set up the parameters you want to use and we will go from there. I will provide everything you need, welding machine, tensile tester, bend tester, RT, PT, VT whatever you want to test it with. You can also clean it anyway you desire.

The pic below is what I am looking for.

Come on down and let's have some fun!

 

^rad. Agreed, doesnt seem right to drag someones rep and work through the mud.- but I am anxious to see the outcome- but in truth we are building hot rods not rocket ships

 

Cool! I will check my frequent-flier miles!

 

What the hell happened to "Oxy-Acc and coat hanger"?

 

I do it exactly the same way as Scoty with one exception, my mig torch is always facing the direction I am going pushing more shielding gas on the weld.




I never let off the trigger and you can see from the heat signature that is hot as hell!




My technique is to start the puddle, then pull the molten metal about halfway past itself, then drag it right back to each main weld puddle. My mig torch is pointed in the direction of travel, but there are cases where I do it "backwards" and still produce the same weld. This is not TACK TACK welding at all.

 

Thanks Gimpy. I'm glad a person who knows Skoty and what he exactly did chime in. I was mainly gonna use this technique for aesthetic purposes but it's good to know that his welds are stronger than what people believed it to be.

Thanks for all the input you guys gave as well. Your guys's welds put me to shame. Oh well, time to chop up some broken bicycles and practice, practice, practice!

 

I don't mind a thorough technical explanation from the experts, but I think it was already pointed out, and rightly so, this forum isn't about welding the engineering wonders of the new World Trade Center, or the airframe of Spaceship One (yes, I know has a carbon composite airframe).
Welding conversations on the HAMB are about sheetmetal, header tubes, suspension links, roll cages and chassis boxing plates. NONE of those is under the same inspection criteria that you will find at Boeing or One World Trade Center. Let's skip the demoralizing commentary and talk about things we can learn without pursuing our Masters in Welding.
I know this for certain, what you say wont pass X-ray based on your assessment of an internet photo or video, will absolutely serve it's intended purpose until someone deconstructs it by force or flame. NO ONE can inspect a weld over the internet.

Now I do understand what was mentioned about the "coins" being too widely spaced and how it could result in micro cracks at each overlap. That makes sense, but what does it mean to the guy down the block welding in air bag mounts? Not much. One, he doesn't care, or he would have had a certified weld inspector check his work. Two, I learned what I know through experience. It's the culmination of instruction, tips and pointers from many of my elders, plus a few good discussions like this one. In that time, I have seen my work, and that of my teachers, tested in the real world, not by some inspector or X-ray machine. (the inspector signed off, by the way) One chassis car we built packed 1100 HP and 175mph 1/4 mile speeds just before it bounced off both walls at the track one day. The driver climbed out, job one, and then the car was dismantled for post-mortem. Not one run of tubing was straight after the crash. Not one single weld failed or even cracked. That cage DID exactly what it was supposed to. I'll keep doing what this particular mentor tells me. If NASA calls, I'll let you know. For now, I'll try to lose my bad habits, strive to be just as careful welding sheetmetal as I am a roll-cage, and make both turn out better than anything I've done before.

 

Quite possibly one of the all time BEST posts/replies in the history of the HAMB.

Bravo.

 

I've enjoyed reading this thread and all the opinions but now we have a motor race. So is this challenge gonna happen? I have no idea what Friction stir welding is but I want to see the results of this duel.

Pete

 

Very nice...now lets see it on thin sheet metal without major distortion!

 

I have been using the continous C patteren, CCCCCCCCCCCC no stops or trigger stops. It looks like a braid to me. done with a mig welder.

 

Back on page 3 the question was posed about running a continuous root pass and then going back over with a "pretty" cover pass. This brings up a point that up until now I have not seen discussed. If the metal is thick (more than 1/4"), it may be necessary to run multiple passes; depending on position, desired build for finishing, etc. On typical hot rod / race car structural materials, it is never necessary to run multiple passes...so DON'T.

If you look next to any unfinished weld pictured in this thread (or anywhere for that matter), you will see an area where the base metal has been discolored from the heat input. In welding, this is referred to as the HAZ or heat affected zone. In general metallurgy, those colors are referred to as "temper colors" because the metal has undergone a change in state and grain structure. The whole idea of proper fit, cleaning, etc. is to allow for a full penetration weld with the minimum heat input. Running a second pass to make a pretty cover weld is doubling the heat input and creating more of a HAZ than a good, continuous single pass. So, too is a lot of side motion in the weld technique. All we really need is full penetration at the root (fillet welds being an exception), not a lot of weld laid out to the sides on the surface of the material.

I'm NOT a certified welder, nor do I play one on TV, but I have been teaching basic MIG and TIG welding with a CWI/CWE for years; and I listen and pay attention to what I am doing. I have been building mild steel and 4130 race car chassis and components for 20+ years, and I have learned this lesson the hard way.

Weld it once, weld it right, and leave it alone.

 

Here's another video from the welder in the op. Check the cut away view of the welded material to see the penetration that he's getting.

http://www.youtube.com/watch?v=PI3pZxoPRvA

 

Just some reminders of what we're NOT trying to do.

 

^^That second picture made me cringe!

 

The welds are nice uniform welds. They are short arc (or short circuit) probley with .035 ER70 wire and the process is called stepping the weld. The gas is proberly 75/25 mix. Stepping is starting your puddle and allowing to build up to your desired weld size and then moving forward a small bite and returning back and allowing the puddle to build back to the desired size. Oh staggered weld is a T-joint that has stitch welds on both sides of the T-joint. What ya'll were going for was repeated tack weld early in the thread. And I can tell you that is wrong it is a nice weld and will hold up well

 

Friction Stir welding is a solid state process utilizing zero filler metal and no shielding gas.

This type of welding does not melt the metal, instead it creates plastic flow by "stirring" the metal creating a defect free weld that is stronger than an arc weld with an almost non-existent HAZ. In many alloys the FSW is stronger than the base metal but still retains the ductility of the base metal.

Below I have attached a photo of a ship that was friction stir welded by us.

Enjoy!

 

This is about the best I've gotten with a mig. I've been welding about a year and a half. Finding out it's all about being consistent.... speed, pattern, etc. I have been experimenting to find the technique that works for me... this was done moving forward and then backing up and welding back into the puddle like others have mentioned.

 

You know...I'm not meaning to be an ass or anything...but who cares about welding something with a process thats totally out of our reach?

It's pretty looking and high tech but ultimately useless.
I'm doubtful that Miller will be bringing out an inexpensive 110v home version any time soon!

I'd much rather watch a true master with a gas torch and a steel rod work magic with human hands.