How strong is a clean 3 pass mig weld vs one with a poor root? part 2

[@john-smith.]

The video quality, and lighting look great....thanks.

[@Jahee-Official]

Just noticed you made a part 2. (second vid I ever watched made by you) Hope you'll see this post, it's a copy-paste from my comment on your part-1 vid. (this comment is a copy-paste from your previous vid) Thank you for creating this video! Very informative at an entry level. I shared/featured it on my small Budget DIY discord server. In the end of the video, you mentioned what homegamers/DIY people tend to require from their welds. I could be considered a homegamer/DIY person. But I don't have a fancy mig welder with gas. I use a very cheap flux-core mig welder. It doesn't even have a name, it just says "130" on it. 1 freespin knob to maybe adjust wire speed (probably broken from the factory) and 2 switches to adjust the power. My welds ALWAYS have plenty buckshot. Which is just mandatory, because of welding with flux-core wire. Very often, my welds also look just poopy. But it's a very different kind of poopy. I can't re-create your "terrible" welds, because gas is always included. I will also only weld metals up to 3 mm thick, which is on occasion somewhat structural. (bicycle trailer, which once carried up to 250 kg, used it for many dozens of km like this) I do get all the penetration in my welds, and I'm currently at an expert lvl for stitching holes back up. I wonder if you could do a follow up video with a flux-core welder with basic settings, and horrible looking welds. Because when I do destructive testing, I tend to break/snap the base metals, not the welds. Even if the welds look REALLY ugly.

[@makingmistakeswithgreg]

I believe I responded to this post somewhere else, but I do have a ton of videos dealing with flux core and testing under my channels playlist titled flux core. I would start with that list and work your way through it. In a nutshell the defects of a weld may or may not matter, it really depends on what you’re welding. You describe ugly welds, but ugly welds that have some root fusion may hold up fine depending on how you stress them. If you’re also welding on thin material that may also hold up far better than thicker material from the simple fact you can’t put enough force on the weld to have it fail. It’s common to “over weld” aka oversized welds on thinner material, and in such cases weld defects become less significant. The problem with defects is they introduce a variable that creates unpredictable results. Undercut, porosity, lack of fusion, poor penetration, etc, are undesirable and can cause premature failures. Simply practicing enough to be capable of eliminating them can result in significant strength gains in a persons welds. Everyone should strive to do the best they can and if something goes wrong with a weld, fixing it is the right thing to do.

[@sk18mangaming]

I appreciate you reading my cimment and making a video about it! This provided what i would consider very valuable knowledge! It really goes to show just how important a good first pass is.

[@makingmistakeswithgreg]

The first pass is definitely super important. Even though a poor root (but clean cap) still handled a bend away from the face, the overall reduction in strength is definitely significant. Weld defects add unpredictable variables, and that’s the last thing you want to add to something you want to have hold together 😀

[@darenscott1718]

Keep em coming! Love the content. I'd really like to see you revisit the .035 dual shield with the ESAB 235. I feel like that machine should have enough oompf to get in there.

[@makingmistakeswithgreg]

I have some more .035 wire and I am definitely going to be attempting that soon. The rebel 235 has no problem hitting 230+ amps on my generator. Due to power factor correction I am able to get so much more power out of my generator.

[@ypaulbrown]

hello Greg, always enjoy your to the point videos with great information, cheers, Paul

[@dusty1498]

Hey Greg I bought one of those ninty nine dollar simder arc 200 welders off the Jungle site and I am really impressed in how it welds! I had to swap out the stinger and make up my own leads for it because the ones it comes with are super short and I think by the weight of them it must be copper coated aluminum. I had a little project using 3/32 7018 and It welded amazing for what it is,I did heat the rods them in my rod oven! The arc force knob does seem to affect the Puddle.The only negative I see is rods seem a little harder to strike as in you have to drag the rod a little longer especially on a used rod!

[@makingmistakeswithgreg]

It’s pretty common to have rougher starts with the “Amazon specials”, but as you found out they run really good once the arc is lit. Definitely worth it for the price, little stick welders are generally worth it. The cheaper MiG machines are often far poorer performing and less useful.

[@michaelwhiting878]

How do you think this clean 3 pass MIG weld would compare to a 3 pass TIG weld of similar size? I’m thinking at least the Root Pass would have much better penetration, and therefore a much stronger weld. Perhaps a heavier duty Bending Bar is needed, for these multi pass-welds, but one would have to consider what the Vise can handle. That’s a pretty stout vise you have, I would hate to see it fail.

[@bruced1429]

how about a test with an edge bevel . I would expect more strengh.

[@makingmistakeswithgreg]

I am editing that video now. There are a lot of variables with bevels and hopefully the video gives a lot of info on that 😀

[@RG-ce5hj]

Love the video! The shots with your hand "talking" reminds me of White Fang on the old Soupy Sales show! Good memories!🤓

[@bearkawiboy6246]

If not done already, I’d love to see some mig weld strength test vs Stick with various electrodes and wire size.

[@makingmistakeswithgreg]

I have done that over a bunch of videos, but not as a big shootout. If you hop on the channels main page, click the playlists tab, and click the weld break tests tab, most of the bend tests are in there. There are also a ton of comparison videos under the comparison/shoot out tab. To save you some time, from a functional strength perspective the same size 7018 and the same size MiG weld perform extremely close. 60 series rods are significantly weaker overall. Flux core self shielded wire tends to be weaker than both 7018 and Mig as well, mainly due to limits of the wire diameter most home hobby machines run. Where Mig tends to be a problem is it’s capable of producing welds that visually look ok but have very poor fusion. This makes it incredibly difficult to correlate strength based on looks. With stick the visual look is a far better representation of fusion, so how a weld looks is more easily used to determine weld quality. This really stresses the importance of doing a cut and etch or break test of MiG welds to determine what’s going on.

[@sebastianleicht]

Nice video as always. Thanks for that follow-up!

[@hhoverdrive1]

You got me wondering if there is a difference or what would be the difference between dragging or pushing.

[@makingmistakeswithgreg]

There are subtle differences between the two. I will definitely test that. From a realistic standpoint I don’t believe they will be hugely different on 1/4in and thinner material. I doubt more than a 2-3% difference, but testing will have to confirm that.

[@fastbusiness]

Not related to this video, but I was wondering about this: I think you have used 6010, 11, 13 and 7018 individually in bend tests in some of your past videos. How about testing one where you make the root pass with 6010 or 6011 and subsequent passes with 7018. Some of the pipe welding videos I've watched show making the root pass with 6010 and all the fill and cap with 7018. They don't say why it's done that way, but I assume it is because they get better root fusion. Thanks.

[@jake-mv5oi]

kzbin.info/www/bejne/jXuUmZqcqMiJm5osi=ETYW38kU2yWCfX1Y

[@makingmistakeswithgreg]

So pipe welding has so many things that are unique to pipe and not applicable to making stuff every day. They essentially weld open bevel, open root, butt welds. Very few welds people do at home would be similar. The situation they work with is also not stressed in the same way you might see with something at home. Which is why it’s important to be able to understand why they do things the way they do. 6010 is often used on a pipe root (or welded all the way out) because it’s fast, it can be run downhill, and it handles poor fit up/poor material well. Making stuff in the home shop we often have better control of fitup, how clean stuff is, and we don’t run downhill or open roots. The benefits of 6010 as a first pass are more limited at home. 6010 is significantly weaker is actual testing than 7018, which also limits its use. If you were to do a fillet weld with a 6010 root 7018 fill and cap you will have great strength/performance on mild steel, however 6010 root to cap will not perform close to 7018. Not to mention 6010 shouldn’t be used on higher strength steel either. The reason why pipe is often welded different than other welding (like structural steel) is due to the requirements of the weld performance, the materials used, and how the welds will be stressed. The stress a weld on a pipe buried in the ground sees is completely different than say a fillet weld on a trailer (or a bridge beam). What is deemed acceptable for one thing is completely wrong for another. Even more interesting is some people weld pipe with 7018 downhill, which the manufactures literally specify 7018 is not suitable for downhill welding. You will never see a weld procedure in structural steel specify downhill 7018. So I guess the general idea is if what you make needs strength, weld it with 7018. If strength isn’t a huge concern, or it’s poor quality material, weld it with 6010/6011.

[@fastbusiness]

@@makingmistakeswithgreg That makes sense. I didn't consider the different stresses involved in pipe welding vs. structural. Thanks for taking the time to explain how it works.

[@bratvlad]

Part one ? thanks

[@makingmistakeswithgreg]

It’s now in the description, KZbin didn’t want to link it for some reason, it should work now.

[@douglasthompson2740]

Hello Greg, I have never tried it but looking at these results with lower powered machines it brought to mind, what would happen if you used a torch and heated that junction to just under red hot then ran the root bead? Normally I would just 'V' out the join to get better penetration but you have me wondering. It would be interesting to see how much that would increase warpage as well. I have preheated to three or four hundred in the past but never up to or above a thousand.

[@makingmistakeswithgreg]

So I covered preheating plates in this video: kzbin.info/www/bejne/mJuZaIhnlLyoh68si=7VSur529XzkgEL__ . I also covered preheating plates and welding at 140 amps in this video: kzbin.info/www/bejne/eanbeWmohr2gZ7ssi=np9T9k8CPGq3TxNB . Preheating plates can lead to increases in root fusion, which increases the strength requires to break a weld towards the face. The preheat is likely not a massive gain in strength though. In the video where I welded 140a on 3/8th plate, the preheat saw no real measurable gain in weld strength. There becomes a point where low amperage is simply too low to benefit from preheat. If the plate was red hot or near red hot I have a feeling the solidifying weld would suffer from poor grain structure and thus perform poorly. This is why it’s common to see bend tests fail when someone runs a ton of passes back to back without allowing the plates to cool. Beveling plates can be effective however it depends on many factors. On a fillet weld where the bevel is only on the top plate, the effectiveness will be limited because the bottom plate is still the same thickness. The bevel reduces the material thickness so it’s possible to fuse the material with less amperage and to be able to fit multiple welds.

[@theseldomseenkid6251]

Shop Question. Since winter is almost here. Do you like the heater you are using in this video? If so, can you share the make and model?

[@makingmistakeswithgreg]

So I actually have 3 heaters I use in the shop. A “big buddy” propane unit, a dura heat kerosene heater (probably the one in the video, I don’t have enough reception to see for sure), and a large 200k btu mr heater propane unit. The black kerosene unit is really nice because it’s super quiet and it doesn’t smell at all like kerosene which I really appreciate. I should do a video on this to help everyone out.

[@davidseslar5798]

previous video: kzbin.info/www/bejne/gmOnqWSNnsyZe5Y

[@thegarbagegladiators4735]

3 people love porosity ...

[@makingmistakeswithgreg]

Haha some people like Swiss cheese welds 😀

[@georgesimpson3113]

No link to the first vid... it's part 2. You never say what wire you are using... ER70S-2 - ER70S-3 - ER70S-4 - ER70S-6 - ER70S-7

[@makingmistakeswithgreg]

Sorry, KZbin seems to not like it when I post links to my own videos lol. I fixed it, it may work now. It’s er70s6 I believe. The wires won’t be much different in bend testing between s6 and s2.

[@ypaulbrown]

yeah, and when you bust more than a couple of x rays, you are off the job.....

[@makingmistakeswithgreg]

That’s for sure 👍

[@Oldtech51]

Some reason you don't bevel the vertical plate or open the root up?

[@makingmistakeswithgreg]

I have a video out soon that covers running gaps and bevels. The problem with doing that is consistency. Starting off with a straight 90 degree intersection of a root clears up any debate to the performance the average person would see. When you run gaps and bevels minor differences such as gap distance, bevel angle, needing to tack it to maintain gaps, and if the gap closes during welding are all variables that can change the results significantly. This video combined with the first part basically shows you should expect a 30% + reduction (or more) in strength loss with a poor root. Also, keep in mind that bevel or gap left in the plates will only boost the strength in a bend towards the face. It won’t help it much if at all when bent away from the face.