Stringer vs weave

[Dan Dubeau]

I watched an interesting video the other night, and though I'd share and maybe spark a discussion because I know there are some knowledgeable people here and I want to learn more of how it's actually done in the real world. What's your opinion or preferred methods?

I'm primarily a self taught welder. I've read a few books, got a little bit of hands on teaching from a few coworkers and friends over the years, but for the most part, it's been youtube, forums, and books for mig, tig and stick. I don't consider myself a great welder, but am confident enough in my abilities to work within them, and seek out expertise when I'm beyond them. I've always preferred running stringers when Stick welding, I seem to recall reading that it was preferred, and the stronger correct way for structural stuff years ago, but I'm not sure where I read that. Weave being more for pipe work on cap passes? For looks more than anything.

Seeing as how I don't do any pipe welding I've never done any weave, but on my recent forge firepot build a few weeks back I did give it a try. While it was a fun skill builder, and the results didn't really matter as it's non structural and hidden, I will stick with stringers for critical welds after watching that video.

Here's my 1st attempt at a downhill 1/8" 7018 weave on 1/2" plate. This is the 3rd pass on top of 3 stringer beads. Totally overkill for what it is, but I was having fun, and don't get to burn a lot of rod so, this was more for entertainment than function.


Anyway, I thought the video, while long, was pretty informative, and I loved the analysis and testing of samples part. Reminds me of my metallurgy classes in college where we did a few labs on heat treating and destructive testing of various steels. Fun class and I wish I had access to or got to do that kind of stuff now.

 

[phaxtris]

Those are pretty big weaves for a flat position weld with slag

Fillets in the flat/horz/overhead are normally done with stringers on all processes
Fillets in the virt can be done with stringers but are normally done with a weave, again with all processes

Downhill is uncommon for 7018, there are some special procedures for it but they are far and few between, 6010 downhill is often used for pipe roots

Groove welds are a crap shoot, open roots/backing strip first pass is a Stringer, first few after most likely a Stringer with a very small weave (not enough room for indv stringers) then depending on the procedure, position, and how much room is in the joint it may be stringers or it may be weave. You also have to conform to the engineered procedure, if it says all stringers then it's all stringers, etc


Weaves can be problematic in general welding (asside from virts), the chance for inclusions (stick/fluxcore) and/or lack of fusion is high

I imagine those weave welds failed the sharpy so easily because they most likely had some inclusions or lof internally


Generally speaking the rule of thumb is flat/hor/overhead are stringers, virt is a weave

 

[Dan Dubeau]

Those are pretty big weaves for a flat position weld with slag

Fillets in the flat/horz/overhead are normally done with stringers on all processes
Fillets in the virt can be done with stringers but are normally done with a weave, again with all processes

Downhill is uncommon for 7018, there are some special procedures for it but they are far and few between, 6010 downhill is often used for pipe roots

Groove welds are a crap shoot, open roots/backing strip first pass is a Stringer, first few after most likely a Stringer with a very small weave (not enough room for indv stringers) then depending on the procedure, position, and how much room is in the joint it may be stringers or it may be weave. You also have to conform to the engineered procedure, if it says all stringers then it's all stringers, etc


Weaves can be problematic in general welding (asside from virts), the chance for inclusions (stick/fluxcore) and/or lack of fusion is high

I imagine those weave welds failed the sharpy so easily because they most likely had some inclusions or lof internally


Generally speaking the rule of thumb is flat/hor/overhead are stringers, virt is a weave

Thank you for the info.

Not having a formal education in welding, or doing it for a living I don't have a solid foundation of knowledge to build from. Or the repetitious work to drill it into my head over and over. Just fragmented tips and tricks I've picked up over the years, and probably a few bad habits thrown in for good measure. I always have a hard time remembering this stuff, because it is sometimes months/years between uses. Usually when I start something I'm unsure of I'll look up the details and procedures online, but the internet can sometimes be a source of conflicting info.

Yes, that was a (too) large gap to fill, but it was mostly playing around on my part to see if I could make it look nice and homogeneous while playing manipulating the weld puddle to build some muscle memory skills. I'm pretty sure I did the last (maybe 2?) corner uphill, but can't remember 100%. I did the welding on that project in fragmented free time over a weekend and don't 100% remember all the details. On non critical personal projects like this I like to try different things and see how they look, and work out. Making mental notes along the way that will surely be forgotten the next time I need them.

As to how the weave failed so bad, I kinda thought slag inclusions too. Just a gut reaction that the more you manipulate the puddle around the more opportunity you have to invite slag into it. Seems like common sense, but again, this goes back to my lack of education and experience and why I wanted to start this discussion to learn more and pry some knowledge out of the more experienced around here.

 

[phaxtris]

Oh no i was referring to the weave in the video, it looks like he is trying to make an inch or more wide cap.....and slow, I wonder what his machine is set at

that open corner weld you have done is weave territory, another weave on top...uphand, flat, or even slightly inclined would pretty it up...the open corner aspect changes things a bit

What you have done. With the down hand 7018 and a weave is pretty unusual , lots of chance for inclusions, low penetration (not a big deal here) and very low build up.
Down hand and 7018 is just generally not accepted, there are instances where guys will "cheat" and throw a down hand pass to bridge a gap and then complete the with up hand welds, it's not actually correct, but it is done, there are also procedures involving downhand 7018...but again far and few between

That weld does actually look decent, it just needs more fill, I find it pretty common that guys literally just need 1 more pass, a lipstick pass, and it looks great.....in this case you won't get the build up running down hand tho, needs to be any position other than down


I should note...horizontal welds are absolutely never done with a weave

 

[CWret]

Jason (in the above video) and Rob Moffat are regulars on Weld.com. I’ve learned a lot from them as well as from Jody on Welding Tips and Tricks. Most of the time those guys remind me how little i know about welding.
Thanks for posting the video Dan - the testing was particularly interesting. As Ryan pointed out - a weave bead has it’s place but as much as possible i try to position the piece to avoid vertical. I also avoid a fillet weld except for something that is temporary. I do often use a small zigzag (which is really a weave) just because it makes for a nice looking MIG bead (not as pretty as a good TIG - but my TIG is far from pretty).

 

[phaxtris]

I also avoid a fillet weld except for something that is temporary

you may be thinking a fillet weld is something other than it is, most welds in general fabrication are fillet welds.

 

[CWret]

Maybe my terminology needs some work. I use a fillet if i have access to both sides. I say temporary, meaning a brace that i intend to remove because a fillet is easier to grind or gouge out. Otherwise i take a bit more time to use a groove or bevel for full penetration.

 

[phaxtris]

you are grinding and putting a full pen weld in every joint you weld ???

 

[CWret]

Yes full pen - i occasionally weld 5/8” flat bar but mostly i work with 1/4” materials - home hobby guy now. When i was supervising heavy civil (deep foundations, sheet piles, bearing piles, structural steel) it was union work and i never struck an arc.

 

[phaxtris]

are you always splicing materials ? or are you just concerned you don't have enough amperage to get the job done?

 

[Ironman]

Is you polarity correct for the 7018? Penetration is better with electrode negative. Electron flow is from negative and added to positive side so there is more heat into the work if E.N. but EP will fool you with a smooth low pen weld.
I would have used a 6010 root pass, and uphand 3/32" 7018 rod at a lower heat and made several uphand passes to fill the joint.

 

[CWret]

Ryan - yea i guess i do use fillet welds quite a bit. Just now looking at the stand i made last year for my 1,000 lb bench top mill - i see lots of fillet welds. But yes - if splicing its a full pen. My Millermatic 220 is maxed out at 200 amps on stick (but i mostly do MIG and a bit of TIG).

 

[phaxtris]

Ryan - yea i guess i do use fillet welds quite a bit. Just now looking at the stand i made last year for my 1,000 lb bench top mill - i see lots of fillet welds. But yes - if splicing its a full pen. My Millermatic 220 is maxed out at 200 amps on stick (but i mostly do MIG and a bit of TIG).

i was just a little confused how it was that you were always doing full pen welds, when most welds on most things are just fillet welds....200a for stick is plenty, lots of overhead to run 5/32 comfortably !

Penetration is better with electrode negative.

generally speaking this is incorrect, reverse polarity with most rods has deeper penetration, 7018 included. Your understanding of electron flow is correct, and where the heat is concentrated, but the outcome is opposite to your conclusion.

 

[Ironman]

i was just a little confused how it was that you were always doing full pen welds, when most welds on most things are just fillet welds....200a for stick is plenty, lots of overhead to run 5/32 comfortably !



generally speaking this is incorrect, reverse polarity with most rods has deeper penetration, 7018 included. Your understanding of electron flow is correct, and where the heat is concentrated, but the outcome is opposite to your conclusion.

Well, looks like I got it backwards. But as you said, generally speaking. I've had too many oldtimers tell me straight was the only way to go, so I just read up on it the Lincoln site. Polarity and rod angle are important on penetration.....unless I'm wrong.

 

[phaxtris]

Well, looks like I got it backwards. But as you said, generally speaking. I've had too many oldtimers tell me straight was the only way to go, so I just read up on it the Lincoln site. Polarity and rod angle are important on penetration.....unless I'm wrong.

They may have been referring to an open root with 7018, in wich case straight polarity is the "trick" for the root, although I don't recall it actually being in the weld procedure.....might be why it's the "trick"...7018 in reverse is pretty hard to root

That trick only goes for the root, all the other passes are done in reverse polarity, I have not actually read a procedure that allows 7018 in straight polarity...not to say they don't exist, I've just never seen one in my 19 years as a welder

 

[Ironman]

Sigh.
Now I had to go and look at my welder to check, yep, I've been set up electrode positive for 20 years

 

[Dabbler]

@phaxtris I tend to fillet all my base metal before welding - but here's my excuse. I only really weld a couple of times a year, so my technique (in polite terms) sucks, and I'm a slow welder so I tend to weld at lower voltage and slower feed rates. I also grind my welds flat 90% of the time, for functional or aesthetic reasons.

I am beginning to learn to use higher voltage and feed rates using John Nielsen's welder, and I like the results.

 

[StevSmar]

I watched an interesting video the other night

That was really interesting! I don’t know what the numbers mean, but it seemed conclusive that stringers results in a better weld.