Advice on choosing proper rod diameter/size,

[Soundguy]

yep.. i use 1/16 on 30a and don't linger any. I use 5/64 up to 70a for filling and small welding on 1/8" and even up to 3/16 if it is light duty stuff.

soundguy[

QUOTE=k0ua;2174009]I use 1/16 6013 for light sheet metal, on as low as about 22 amps for low penetration, moving fast, trying like He** to keep from burning a hole stuff!
1/16 can work for up to 40 amps, maybe, anything more than that is just heat and light..poof!. 3/32 for the majority of my welding, and 1/8 for when it gets a little heavier, like 3/8 inch. I have never welded 1/2 inch material, I guess that is where the 5/32 and 3/16 and a bigger welder than mine start to come into play. I suppose I could bevel well and use 1/8 inch 6010 or 6011 to get there.
James K0UA[/QUOTE]

 

[Soundguy]

However, even though the breaks weren't in the exact spot, they were close enough, maybe shifted over by 1/4"+.

...s to the inclusion of the dark coloring in the weld itself, some form of contamination.

many times the weld is hard, and tougher than the sourounding metal.. making it stress crack right onthe edge of the weld.

the dark inclusions could be slag that didn't get burned off or chipped off the root pass befor ethe tie passes went on.

soundguy

 

[Big Wave D]

many times the weld is hard, and tougher than the sourounding metal.. making it stress crack right onthe edge of the weld.

the dark inclusions could be slag that didn't get burned off or chipped off the root pass befor ethe tie passes went on.

soundguy

I'm going with your answer A. I use my slag hammer and wire brush religiously. I think I was running way to low on the amperage setting. It was hard to strike my arc and keep it going, but I was having problems with burn through so that's why I kept backing off.

It seems that I need to expand my choices of rod size. I'd just always seen everybody using 1/8" rod with this sized welder, which is what I own. (Monkey see, monkey do)

Had I used a smaller rod on the root pass, I would have gotten proper penetration using the correct heat/amperage setting. I could then have maybe finished up 1/8" or stuck with 3/32".

The more I read, the more there seems to be only guidelines and not rules. "Rules" are whatever is working for you at that moment in time on what your working on, tomorrow will mostly likely be close but not the same. As they say, "Your mileage may vary..."

 

[Soundguy]

i dunno. I'd say I use 1/8 rod 95% of the time... what were you welding on? 3/8 bar stock? i'd not use anything smaller than 3/8 and hope to get full penetration.

alot of it is technique too, and speed to prevent burn thru. I generally run 90-110a on similar stuff. if I am welding thicker I might jump to 5/32 and upp the amps a bit.

soundguy

 

[Chilly807]

I've had some interesting experiences lately with out-of-position welding, I think maybe some of that may carry over here as well. First instance was vertical welds using the MIG last weekend. With the right heat settings to get good penetration, I was having trouble with sagging, the weld looked like the wrath of God. So, backing off the heat a little, I was getting cold welds, too much height and not enough spread. Tried increasing speed a little, then it was a high stringy looking bead (outrunning the puddle).

Finally I got fed up and used the technique I've had success with on thin metal, which is a short burst of weld, allow the metal to cool a couple of seconds, and hit it again for a few seconds, repeating for the duration of the joint. I was expecting a lousy looking weld after I brushed it off, but it was actually not bad at all. I got the bead profile I wanted, no sags, and good penetration from what I can see from the back side.

The second light bulb moment was using the stick at about 120 amps DCEP, 1/8 7018 to weld 3/8 plate to the end of 1" hot-rolled round stock rods. The first couple of sections had the round stock undercut more than I like.

I nearly always use a weave pattern when I weld, I have better speed control that way, and a more consistent bead profile.

I remembered something someone here said about manipulating the puddle to steer the heat where you want it. So, I figured that undercut meant too much heat on the round stock. I tried spending more time with the rod on the plate side of the puddle (just enough time on the round stock side to allow the puddle to form up into it), and I had no more undercut, nice weld profile, and a good solid looking job after three beads around.

The whole watch-the-puddle thing is probably the single most helpful thing I've learned about welding. It doesn't matter a hoot if you think you have the right speed or not, if the puddle of molten metal isn't right, you don't have a chance of getting a good bond that looks even remotely good.

I've heard people say that it doesn't matter if the weld is pretty or not as long as it's strong. I personally feel that's a crock of sh**. Most ugly welds aren't as strong as they could be, although they may be strong enough to do the job. I take pride in my work, whether it's for me or someone else, and if it's not a decent looking weld, I'm liable to grind it back and try again.

It doesn't have to be perfect, God knows I'm not either, but it should be presentable.

Another :2cents: tirade.. thanks for letting me rant

Sean

 

[Chilly807]

However, even though the breaks weren't in the exact spot, they were close enough, maybe shifted over by 1/4"+.

It may have been heat stress in the metal, or dis-similar material that didn't like being joined by that particular rod composition. The fact that the break was slightly off from the original spot says that could be the problem. I could be wrong on that, just a semi-educated guess on my part.

Sean

 

[Big Wave D]

i dunno. I'd say I use 1/8 rod 95% of the time... what were you welding on? 3/8 bar stock? i'd not use anything smaller than 3/8 and hope to get full penetration.
soundguy

The lift arms in questions were 2.5" x .5" x 31". I would think that 1/8" rod wouldn't be 'overpowering', but it was giving me fits for trying to get my root pass down.

My welder was given to me, so that's a huge plus. If I have a complaint, it's that it has no ability to dial in on amperage. You have the given settings and that's it.

Just need more time, plain and simple.

Thanks to all who have added to this post. I'm trying to absorb what I've been reading and putting it to use.

 

[Shield Arc]

The lift arms in questions were 2.5" x .5" x 31". I would think that 1/8" rod wouldn't be 'overpowering', but it was giving me fits for trying to get my root pass down.

My welder was given to me, so that's a huge plus. If I have a complaint, it's that it has no ability to dial in on amperage. You have the given settings and that's it.

Just need more time, plain and simple.

Thanks to all who have added to this post. I'm trying to absorb what I've been reading and putting it to use.

In the vertical position I can see where it takes some experience. That will come in time.
Flat, horizontal, and over head it shouldn't be an issue at all, with the proper joint prep. I wouldn't think twice about running 1/8 inch rod on 1/2 inch plate, in fact that's the very rod I'd grab for vertical, maybe 5/32 for the other positions. Big Wave remember there is no shame in spending a little time in removing a part, or standing it up to make the weld in the flat position! Littler tougher if we're talking battle ships! :laughing:
I have had steady diets of splicing 36 inch I-beams, generally there is always a crane or at least a forklift on site, it is mush more productive to roll the beams than weld in position!

 

[Big Wave D]

In the vertical position I can see where it takes some experience. That will come in time.
Flat, horizontal, and over head it shouldn't be an issue at all, with the proper joint prep. I wouldn't think twice about running 1/8 inch rod on 1/2 inch plate, in fact that's the very rod I'd grab for vertical, maybe 5/32 for the other positions. Big Wave remember there is no shame in spending a little time in removing a part, or standing it up to make the weld in the flat position! Littler tougher if we're talking battle ships! :laughing:
I have had steady diets of splicing 36 inch I-beams, generally there is always a crane or at least a forklift on site, it is mush more productive to roll the beams than weld in position!

Sadly, Shield Arc, that's what I'd done.

I took the arms off so that I could work on them laying flat instead of vertical on the bush hog.

My technique is just not refined enough at the moment for using 1/8" rod on that initial root pass at the base of the bevel. I either go to slow and burn through or to fast and don't get the puddle working right for proper penetration.

With nothing being there, ie the proper gap, I'm still a bit in the dark about getting one's root pass to adhere and span the gap and not just drip through. Am I trying to lay down one continuous pass or do I go-stop, go-stop?

 

[Chilly807]

My thoughts are this, with any given size of rod there is a range of current settings that it can be expected to perform well within.

For example, 3/32 7018 from Air Liquide is designed to work from 75 to 100 amps, with 90 being optimum. Any less and it doesn't start or burn well, and any more will affect deposition adversely. If you can't get the penetration you need with 75 to 100 amps, you need to go to either a larger or smaller electrode. If you were using 1/8 and getting burn through, there are three possibilities.

1: The material was too thin at the edge of the bevel. You may need a smaller electrode for a root pass, or one that "freezes" more rapidly as the puddle begins to cool.

2: The current setting is too high on the welder. Reduce the amps until you either stop burning through or it doesn't burn well and "lumps" up. If you get lumpy weld and erratic burning, you're too low in amps. Time for a smaller electrode, which will burn properly at the lower current you need to eliminate burn-through.

3: You may have to "stop-start" the weld, which is less than ideal with a stick since it's easy to get slag inclusions doing this.

A 1/8 rod should be used on no less than 3/16 plate, 1/4 is a better starting point in my opinion. The higher current required for the 1/8 won't burn through 1/4 as easily as it will on a thin beveled edge. In other words, use a thicker edge bevel if you need to use a larger electrode. The whole purpose of beveling the edges is to allow better penetration on thick material, and to permit more of the weld to contact the base materials. The root pass establishes the bond at the base of the joint, the subsequent passes reinforce it until the full thickness has been bonded.

I usually leave a small gap in the fit-up, just enough to see through, although it's usually because of a sloppy fit more than anything intentional on my part..
If you have thick enough edges to begin with, it is less likely to drip through. Also, as I posted above, if you're weaving the bead spend more time on the edges of the material than over the gap, since you don't want as much heat where there's nothing to absorb it.

I could be wrong on these assumptions, I'm not a pro welder by any standards. If I am, hopefully somone that does know will point out where I'm wrong.

Sean