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View Full Version : weld bead width and slag removal questions (stick welding)



andy_b
10-10-2009, 09:54 PM
i'm trying to get a little better with my welding and was running a bunch of 6011 and 7018 rods today. i have 1/8" and 5/32" rods and i was running them between 130A-200A according to rod thickness.

when you guys are laying down a bead to fill an area or build a vee up, how wide of a bead do you run? say for 1/8" rods, do you make a 1/2" bead, or can you go wider? what about the 5/32", can you go with a 3/4" bead or is that getting too wide?

if you are laying a bead down next to another bead, not on top of it, just with a slight overlap, do you chip the slag off of the first pass before putting down the next bead, or do you wait until you've laid down all passes on that layer to chip it all off? how about when putting a bead on top of another bead, do you chip the slag off between passes (i'm guessing yes, but maybe there is a reason not to)?

thanks,

andy b.

Dawai
10-10-2009, 10:44 PM
Always chip and brush the slag off.. give it a second or two to cool, it usually pops right off then.

Slag, well that is one reason you can't weld down hill with a stick, the slag runs down and contaminates the weld.

Arc gap is critical, usually about 1/2 to 1/3rd rod diameter if my brain cells are connecting. I weld mostly by sound since I have eye troubles.

A good dry rod is like a Cadillac.

loose nut
10-10-2009, 10:59 PM
Some types of rod can be welded over slag but it is generally a good idea to clean the slag of, less chance of getting slag inclusions and the weld will look better.

Better to stick to stringer beads until you get good at them. If you weave the weld to wide there is a greater chance of weld flaws and the puddle will cool down and have a fish scaled appearance.

Stringer beads are suppose to make a stronger weld and create less weld distortion than a weaved weld.

loose nut
10-10-2009, 11:02 PM
Always chip and brush the slag off.. give it a second or two to cool, it usually pops right off then.

Slag, well that is one reason you can't weld down hill with a stick, the slag runs down and contaminates the weld.

.

Not entirely true, there are some down hand rods available, pipeline welders frequently use the down hand method, but most rods are not good for this use.

MTNGUN
10-10-2009, 11:22 PM
Better to stick to stringer beads until you get good at them. Stringer beads are suppose to make a stronger weld and create less weld distortion than a weaved weld.

Good advice. I'm not as anal about stringers as say, Torker, but Torker convinced me to use 7018 stringers more often and I have to admit that it's easier to lay a consistent stringer bead than a consistent weave. There are exceptions, though. I still use some sort of oscillation for filling gaps, overhead, and sometimes vertical.

As for how wide the bead, that will depend on the rod and the speed. As your speed slows, the bead widens, but if you travel too slow the slag may overtake the arc or even extinguish the arc.

I tend to travel too fast and end up with a narrow, incomplete bead. That comes from years of maintenance welding on rusty, thin, poorly fit pieces, where the name of the game was filling the gap without burning through.

So ....... when I have the luxury of welding in a comfortable position, I try to drag just as slow as possible without drowning the arc.

You mentioned 200 amps ? Assuming we are talking DC+, 1/8" 7018 should be 115 - 130 amps, 5/32" around 160 amps. Less for 6011.

mark61
10-10-2009, 11:42 PM
Rule for width is 2 1/2 times the diameter of the rod. Ei: 1/8" rod can make 5/16" wide weld. 6011 chip EVERY time you stop. 7018 you CAN weld side by side or on top of lower weld during fillet welding but it makes it difficult to accurately see the edge of last bead. You can down hand or weld verticle down with 7018. Won't make a very tall bead. " Peeling is perfect" - when your weld speed/heat/beads just right the slag peels or pops off.

mark61

andy_b
10-11-2009, 12:17 AM
this is an old AC Lincoln buzzbox, no fancy DC option. :) maybe i am running way too high on the current?

NOW i see about the slag running down into the weld when you try and weld going down. i always wondered why i had trouble welding down a vertical seam.

i will now always chip the slag off before making the next pass, as you guys mentioned. will the slag always chip off relatively easily with 6011 and 7018, or will it sometimes take a long time to harden if the metal is real hot from doing a lot of welding. by real hot i mean it melts a 315F heat crayon pretty quickly. i have an IR temp gauge and i think i'll try to get some readings next time i weld some heavier material to see just how hot the metal is staying.

being relatively self-taught, what is a "stringer"?

andy b.

Bob Ford
10-11-2009, 12:50 AM
A stringer is basically a straight drag very little side movement. 6010 and 6011 are about the only rods that you can whip up out of the weld puddle let the puddle solidify then lower the rod and restart the weld. Great technique when running cover passes in pipe welding, though not used much since about 1975.

Bob

Carm
10-11-2009, 05:54 AM
Two rods wide for width is a good average for stringers, and stringers alone are better to fill with- they will cause less shrinkage distortion, provide better grain refinement and generally penetrate more by not being crowded by puddle or slag.
Never let the toes of weld beads meet, attempt to have the toe in the middle of prior beads, or completely cover them as when capping or filling with larger rods.
Part of the rationale for the above is to avoid slag traps. Deep ruts with slag may even need a grinder to open up, or a hot pass technique to rip them out, if using cellulosic rod ( 10's& 11's). Slow hydrogen is not a good rod for the task as whipping will induce hydrogen.
An experienced weldor won't do much interpass grinding or brushing- you learn to assess how much slag can be burned out, you avoid slag traps and use the bare end of the next rod to rake slag away.
Turn up the heat when running downhill and use arc force to control the puddle- the rod should make a low angle to the joint. Yes, you can downhill 18's but I could test thirty weldors before finding one able to pass a lookout.

radkins
10-11-2009, 11:57 AM
The 2 to 2/12 times the rod width is definitely the best and there are a couple of more tricks to add. It has already been pointed out to not let the toe ends of the welds meet so basically what you want to do is avoid stopping the bead in the same spot on each pass, this is also true for starting a new pass. Each time you start the arc (and to a lesser extent when you stop) there is going to be some porosity and thermal shock in the spot where the arc actually starts but if done properly this is very minor and usually poses no problem at all and is mostly eliminated by the next pass. However the effect is cumulative and if each succeeding pass is started in the same spot it will create a very weak area of porosity and micro-cracking that could lead to weld failure, this is easily avoided by starting/stopping the bead in a different place on each pass. On a weld where you must start and stop on an edge tack a small tab about an inch or so long at both ends of the weld, this is done so that the bead can be started on the starting tab and when the pass is finished the bead will be run off onto the other tab. This way you can start the bead in the same spot (on the tabs) at the edge, stop at the opposite edge and when finished you simply cut or grind these tabs off to eliminate the stressed portions of the weld. Another thing to consider when multi-pass welding is to PLAN AHEAD for the next bead! What I mean is, for example, don't let your next to last pass crowd the opposite edge of the weld and not leave enough room for the last bead to reach all the way to the bottom, doing this will trap slag and prevent full penetration of the last bead. Actually another good idea is to never allow the last bead to finish the weld at the edge of the fillet, if the very edge of the weld is finished with the last pass then the transition area from the weld to the base metal will be heat affected (hardened) and highly stressed. The trick is to run another bead (two is better) along the inner side of the edge bead which will tend to stress relieve the transition area, basically you want to finish with the last beads being nearer the center of the weld and never on the very edge. For even more assurance of weld integrity it is a good idea when removing those start-run-off tabs to then grind the surface of the weld, especially the area of the last passes, and then peen to remove the grinding marks which, tiny that they may be, can be stress risers. Just remember that slag inclusion and porosity, along with incomplete penetration, are the most common causes of weld failure.



One other thing that should be covered is joint preparation, NEVER attempt to weld over torch slag or even the scale left from an otherwise clean O/A cut! Doing so is almost always an exercise in frustration especially in vertical or overhead positions. Weld base metal preparation is every bit as important as proper weld technique but is all too often improperly or poorly done or just ignored entirely, to do this is a huge mistake!


Also for that AC machine, did you know there are 7018 rods available just for AC? These AC7018s are not a cure-all for low Hydrogen AC welding problems but they do help quite a bit compared to regular 7018s.

mark61
10-11-2009, 12:10 PM
Try some 7014 rods. I have better luck with them on AC than the 7018s. Has to be CLEAN weld area though!

mark61

MTNGUN
10-11-2009, 12:48 PM
2 - 2.5 times rod diameter ?

That would result in a 0.188" - 0.23" bead with 3/32" rod.

0.25" - 0.3125" with 1/8" rod.

Perhaps correct for 6011, but sounds quite narrow for 7018.

Are we confusing the rule for how much weaving is allowable with a rule for the width of a stringer bead?

andy_b, yes, your AMPS will be higher on AC. Hard to say how much higher because it depends on the machine. Using a Hobart Stickmate (buzz box) and 5/32" 7018, 235 amps struggled to keep the rod lit. The little buzzbox seems to run out of oomph above 150 amps AC. Switch the Hobart to DC+, and the same rod ran satisfactorily at 160 amps.

The special 7018AC rods do have a different personality, even on DC. They are easier to strike and maintain an arc. I find they need more amps and slower travel than regular 7018. I haven't decided whether I like them or not.

It's a lot easier to run 6011, rather than 7018, on an AC buzzbox. I'd suggest using 6011 as much as possible until you get a DC machine. Just bear in mind that 6011 may result in a brittle bead, and should not be trusted on critical structural joints.

Have fun ! ! !

andy_b
10-11-2009, 03:25 PM
It's a lot easier to run 6011, rather than 7018, on an AC buzzbox. I'd suggest using 6011 as much as possible until you get a DC machine. Just bear in mind that 6011 may result in a brittle bead, and should not be trusted on critical structural joints.

Have fun ! ! !

why did you go and say that? :)
i was using 6011, and a friend gave me some 7018 to try. the 7018 does seem to lay a nice bead, but since i am not an expert weldor, i find it a lot easier to run the 6011. i was going to pick up some more 7018 rods to play with, but maybe i'll just keep using the 6011.

i'm not welding "critical structural joints", so if something cracks (i doubt it will in my application) i'm not worried about anything getting damaged or anyone injured. my log splitter has so far held up okay and i just used 6011 for that. :)

thanks for all the other advice from everyone!! i have some more practicing and learning to do.

andy b.

radkins
10-11-2009, 04:23 PM
2 - 2.5 times rod diameter ?

That would result in a 0.188" - 0.23" bead with 3/32" rod.

0.25" - 0.3125" with 1/8" rod.

Perhaps correct for 6011, but sounds quite narrow for 7018.


The special 7018AC rods do have a different personality, I haven't decided whether I like them or not.



Have fun ! ! !



Since the 2 to 3 times the width "rule" is not actually a rule it can be, and often is, interpreted in different ways. I think the most common version is that for best results a bead should not be over 3 times the width of the rod so a weave is obviously going to be wider than that, in any event if the bead is only 2 to 3 times the width of the rod he is going to be in safe territory and that was the point. Of course we have all seen weave beads much wider than 3 times the rod diameter and a lot of welders do this without giving it a second thought, not a good idea IMO but that's just my take on it. :)


Also I have decided that I personally don't care much for the AC7018 on DC but when using AC they have a decided advantage, if DC is available then the AC rod is not the best choice, again JMO.

loose nut
10-11-2009, 08:09 PM
Don't forget 6013 for AC welders, welds nice on buzz boxes and give a finish similar to 7018.

For weave widths, what you are welding has to be taken into consideration. On pipe welding ether roll or position or other bevel joint welds you can weave quite wide, more than the 2 or 3 times the rod diam.

For structural welding flat, overhead and horizontal positions stringers are the best with multiple passes to get the desired size and form, vertical welds can be weaved but commercial work spec's may insist on stringers too.

Get a good book on welding basic's it will show you the proper way to do most general welding jobs.

mark61
10-11-2009, 08:58 PM
Regarding amperage being used, do your machines have an actual amp meter messuring the output? I ask because often here people state using 100+ amps for 1/8" rod. The industrial size welders I use regularly I set around the 65 amp mark for 1/8". 3/16" goes from just below the 100 amp mark ( known to be 12volts!) as far up as 150. Verticle up settings ussually around 15% below flat welding settings. We do have Linclon with both volts and amp meters. 1 of these days I am going to have someone watch and make note of the true output for the various rods. I suspect few if any of these "buzzboxs" put out the stated output. Twoud be better then to discribe how the arc and weld puddle SHOULD be to help understand proper welder set up. Example-Mig welding. Sounds like eggs frying and very little splatter when machine properly set.

Make sense?

mark61

andy_b
10-11-2009, 09:32 PM
i was doing some more practicing tonight, and i was laying stringers. i kind of get what you guys are talking about now. and yes, i think putting down a bunch of stringers instead of trying to do a wide weave seems to work better. i was also cleaning off all the slag between passes and that makes for a nicer weld. finally, i lowered my amperage (or at least the dial setting) to 150A for the 5/32 6011 rods, and it seemed to put a nice bead.

i think i will pick up a box of AC7018 rods tomorrow and see how i make out with them.

i was watching some online tutorials and one of the instructors said he figures you need to go through a good 50 pounds of rods before you get a pretty good hang of it. i guess i need to go through about 35 more pounds. :)

andy b.

radkins
10-12-2009, 12:21 AM
Sounds like eggs frying and very little splatter when machine properly set.mark61


That always seems to be the example people give or sometimes it is the sound of bacon frying depending on who you talk to, anyway it always has something to do with breakfast, but think about it do you REALLY want that MIG weld to be snapping and popping like bacon or eggs frying? :)


Just having a little fun there so don't take me serious but honestly don't you think that MIG weld should have more of a smooth buzzing sound?

radkins
10-12-2009, 12:31 AM
i think i will pick up a box of AC7018 rods tomorrow and see how i make out with them.


They will most likely work better for you but there won't be any major differences, I find them to be smoother and easier to get a clean weld with than standard 7018 when using AC. When you get the chance to use a good DC machine with standard 7018 rods then there WILL be a big difference! I don't mean that AC is not useful, it is, and once you master that AC machine you will find it has made you a better welder (weldor?) when you do get to use DC. There is nothing wrong with the suggestions for the other rods and indeed they all have their place but I think the E7018 is probably the closest thing you will get to a "one size fits all" welding rod.

Carm
10-12-2009, 08:00 AM
"why did you go and say that?
i'm not welding "critical structural joints", so if something cracks (i doubt it will in my application) i'm not worried about anything getting damaged or anyone injured."

A brief description of the number system.
The first two numbers are tensile strength in thousands per square inch. 60xx = 60,00 PSI

The last two designate the flux type, with the third number indicating position of use. 7024 = flat position. A "1" as the third digit means all positions, but not neccessarily ease of use.

A "4" or "8" in the fourth digit indicates addition of iron powder to the flux. These rods will deposit more metal per pass.

6011 is the same core wire as 6010, the flux has stabilizers to allow running on AC. Note that AC yields less penetration due to sine wave reversal. I have never heard that 6011 is brittle.

Stainless fillers essentially follow the number system with a few wrinkles.

Much of the structural steel and Gr.B pipe in average use has tensile /yield values well below 60,000 PSI, so any 60xx rod will suffice, assuming proper prep and application.

As a rule of thumb, the greater the diameter of flux, the less penetration.

As the alloy content of the steel increases, so do hydrogen/atmospheric sensitivity and tensile values. Low hydrogen rods (fourth digit 5,6, & 7) are better suited, as the fluxing precludes hydrogen formation, provided one keeps a tight arc.

Note that high yield steels are often tacked together with 6010 as it has a better ductility. Pipe steels often specify it as the root to avoid cracking.

radkins
10-12-2009, 01:25 PM
I have never heard that 6011 is brittle.



I had to wonder a bit about that one too because I would think that any mild steel wire without the addition of any alloy in the flux such as a 6011 would tend to produce a very ductile bead. My experience with 6011, actually limited somewhat since I just never had much use for it, is that it produces a very soft easy to grind bead that is highly ductile and anything but brittle.

kf2qd
10-12-2009, 03:44 PM
I started out with 6011 and 6013 on a Lincoln 180 BuzzBox. Then used 7018 on an old Hobart Motor Generator unit. Rebuilt a brush-hog using some rod labled 80T-ACPlus. Sweet welds - horizontal and vertical. 1/8 using 110-115 amps (whatever the setting is...) and no craks a year later. And I really abused a brush-hog...

Biggest problem newbies has is trying to rush the project by welding too hot, trying to get a lot of metal in on the first pass. Too cold and it breaks too easy, too hot and it isn't a whole lot better. Remember - you are trying to weld it together so it lasts, nit just get done as fast a possible so you can fix it again.

6011 and 6013 are sometimes referred to as "farm rod". They work on rusty and painted metal because they tend to burn off the fluz a bit slower than 7018 and thus have a little more velocity to the moltem metal coming off the end of the rod. Also makes it harder to weld thiner materials.

loose nut
10-12-2009, 05:39 PM
7018, stainless and other low hydrogen rod are more ductile then 6011 or 6013 which are not low hydrogen rods. Hydrogen makes the welded metal brittle.

In the early days of welding before oxy-acet welding there was oxy-hydrogen welding. This turned out to be a big problem because the weld would absorb some of the hydrogen and become brittle with disastrous results, the welds would break under strain, boilers exploded, ships sank etc.

Welding with 6011 or 6013 isn't that bad but it does limit the strength of the weld.

Open boxes of low hydrogen rods (not 6011 etc. this will cause the flux to fall off) have to be stored at a temp. above 212 deg. to stop moisture absorption which will cause porosity. Even this isn't enough with some types of rod, 308SS for example, so I always heat the end of the rods with a torch to drive of any moisture in it, the act of welding will drive off moisture farther up the rod as you weld. If you can't keep it in a rod oven then that is your next best choice. If you use SS rod with moisture in it you will see holes in the weld about an inch back from the start of the weld.

P.S. I cant confirm this but I have been told that 7018 AC rod will not work on all cheaper AC buzz boxes, it was made for heavier industrial AC machines which are built differently. Cant say??

andy_b
10-12-2009, 08:31 PM
P.S. I cant confirm this but I have been told that 7018 AC rod will not work on all cheaper AC buzz boxes, it was made for heavier industrial AC machines which are built differently. Cant say??

interesting comment, and a perfect time for it, since i just happened to be testing some new 7018AC rods this afternoon. :)
they worked great on my old Lincoln buzzbox. a friend gave me some 7018 rods to play around with, but they had been sitting out and i think they were AC/DC rods. the ones i picked up today were unopened and real 7018AC rods. the 7018AC laid down some beautiful welds and the slag came off easily.

andy b.

Willy
10-12-2009, 11:17 PM
P.S. I cant confirm this but I have been told that 7018 AC rod will not work on all cheaper AC buzz boxes, it was made for heavier industrial AC machines which are built differently. Cant say??

Here's Lincoln's description of their 7018AC rod.



AC? DC? This electrode performs beautifully either way! Lincoln 7018AC is a great choice for low open circuit voltage AC power sources. Cold restrikes are no problem with this versatile, all-position electrode.

radkins
10-13-2009, 12:04 AM
So the AC7018 worked really good for you? That's great I was thinking you would probably like them a lot better but I didn't want to make them out so good that you might expect too much. :) As far as using them with small AC machines, that's what they are known to do best and with something like a classic Lincoln "buzz box" they are a definite improvement over DC7018.



Willy, JMO but I have to take exception with Lincoln's description of those things when used with DC, they are worse when used with DC than the regular DC rods are with AC! The last time I tried to use them (the AC version) with a DC welder was to build up an 18" bearing fit to be re-bored and they were simply terrible. I had loaded my truck and driven over 200 miles to the job site and had loaded 150 lbs of those things by mistake, in that situation I was forced to use them.They did do the job ok it was just that compared to regular 7018 they were a PITA to use, lots of spatter and what I would describ as "harsh" arc characteristics. :mad:

Willy
10-13-2009, 12:11 AM
Yup, I agree 100%. Just more ad hype I guess...tell people what they want to hear.:(

I'll stick with DC thanks.
I must say though that on AC they do work better than the regular DC 7018.

scatter cat
10-14-2009, 12:04 AM
If you can find a copy of Lincolin Electrics New lessions in arc welding it has some good info in it and should answer some of your welding questions. I know there are other newer good books on welding but this is a good one for stick welding.