Unstable arc

[jbwilson]

When stick welding, sometimes the arc flares and I have difficulty in keeping the arc going. This might happen on the same job, where I may do good welds with 4 sticks, but the 5th one plays havoc, resulting in having to grind down the weld to remove slag deposits. This happens mostly when I am doing fillet welds on fairly thick pieces of mild steel and can occur whether I run it at high amps - 120, or low amps - 100.

I am using 3.2mm (1/8th) 6012s. My welder is a Miller Econo Twin using 3 phase power with an high OC voltage - around 75 to 80 amps, so the problem is with me rather than the machine I think. I generally use DCEP. Could my problem be one or more of the following:

1) Old electrodes - The ones I'm using are over 5 years old although I have stored them in a dry place inside my house.

2) Poor quality electrodes - are there differences in quality between different brands for the same electrode specifications.

3) Slag inclusions on the other side of the fillet weld which affect the arc.

4) Wrong current type for the electrode - will AC or DCEN make a difference with 6012 or 6013 electrodes.

5) Welding machine losing it's voltage during the welding operation causing the arc to flurry.

6) Just accept that having a stable arc is a skill that I'll have to double my efforts to master.

 

[dstig1]

I bet you are on DC. Sounds like arc blow which is related to magnetic fields pulling the arc around. AC will eliminate it and there are some other tricks for staying on DC. Wrapping the ground lead around the work is one. There are some others, but that is the easy stuff....

When you see it, try AC and see if it disappears. If so, then it is arc blow.

 

[Shield Arc]

I'll bet it is arc blow too.
How to Prevent Arc Blow | Lincoln Electric

 

[jbwilson]

Thank you. I had the work clamp immediately behind the vertical piece and so arc blow seems very likely. I'll switch over to AC. Also, I think that the welder draws less power using AC than DC for the same amps which should reduce the incidences of fuses tripping.

 

[Shield Arc]

First thing I do when encountering arc blow is change direction of travel. If that doesn't work I move the ground clamp, if that doesn't work I start wrapping the ground lead around the object being welded. If that doesn't work I wrap the ground lead the other direction. Very very seldom do I ever have to heat the weld zone to cherry red, but that always seems to kill arc blow.

 

[Gary Fowler]

Sometimes welding in very windy conditions or with a fan blowing on you will make the arc seem like magnetic arc blow also. I dont think I have ever seen a 6012 rod. This may be a AC only rod. Have to look that one up.

 

[Gary Fowler]

I looked it up and sure enough, 6012 is mostly not used anymore with only 6 percent of the rods made. The Esab site said it was replaced by the advent of 7018 rod. It must be really old rod as 7018 have been around for all of my career life 50 years and counting. I guess that is why I had never heard of it.
Perhaps using some 6011 on AC might cure your arc blow problem or use some 7018. I find that they work a little better on arc blow situations than a 60xx rod.

 

[jbwilson]

I finished off my packet of E6012 electrodes using AC using between 100 - 120 amps with on problems. Then used a new packet of E6013s, again with no problems. An ancient publication describes the covering of E6012s as having a covering of titiania sodium and E6013s with a covering of Titania potassium. Both electrodes are suitable using the flat, vertical, overhead and horizontal position using either AC or DC. I couldn't see any difference in the welding stringers using the same amps between the 2 electrodes, although I thought that starting the arc with the E6013s was a bit easier. I couldn't even see much difference between AC and DCEP, although I noticed that the electrode metal was a little more hollowed out using DCEP.

The same publication describes E7018s as having a low hydrogen potassium, iron powder coating suitable for all positions using AC or DCEP.

I heard about DC arc blow before, but like car accidents, I didn't think it applied to me. Thank you for your advice.

 

[lilranch2001]

My favorite rod is Atom Arc 7018.
I grew up on it and have made it my go to rod whenever possible.
When I first started reading this thread I was wondering about the 6012 rod as well, I could not remember ever hearing about it, maybe it is a "down under" thing

 

[Gary Fowler]

Same here, I love the 7018 for strength and versatility. I keep a small quantity (less than 10#) of 6010 for tacking or open butt root welds but use the 7018 for everything requiring a fillet weld. You can even use it to weld Stainless Steel to Carbon Steel with good results.