Back in the 1970's
Me: " Hey Man these McKay 7018s suck!
They run horrible and sound like I'm Arc Gouging!"
Old timer: It sounds like you're on the wrong polarity?
Me: I don't think so. I mean...I just checked the machine a few minutes ago.
Old timer: Better check it again.
Turns out there were lots of jokers on that job and everybody got messed with.
But I learned a lesson that day.
...that it never hurts to make sure your leads are hooked up the right way ...right before welding.
Checking your leads means making sure that your electrode lead is connected to the electrode dinse or post connection.
If your leads are wrong, you can be welding on straight polarity when the machine says reverse.
7018 rods will run on DCEN or DCEP and some 7018 will even run on AC (on certain machines).
But that doesn't mean they will run like they are supposed to
For structural fillet welds in flat, horizontal, vertical, and overhead, 7018 runs better on Direct Current Electrode Positive DCEP. ( reverse polarity)
7018 welding procedures call for DCEP aka Reverse polarity most of the time.
There are a few exceptions like for 7018 and 7016 open pipe roots where DCEN is specified but 90% of the time, 7018 weld procedures call for DCEP.
Usually the sound gives it away.
DCEP ( reverse polarity) makes a much smoother sound with the occasional crackle.
DCEN ( straight polarity) typically hisses and pops .
The Old Timer noticed the sound right away...Not his first rodeo.
I was green as grass and I blamed the McKay rods.
Today, I am the Old Timer.
Life's too short to weld on the wrong polarity.
I hope this video and article helps you as much as that crusty old timer helped me way back then.
One Big thing I have learned from making welding videos is that you don't need to be the best at something in order to help someone.
All you need to be is a 5th grader willing to help a 4th grader.
Sometimes I'm the 5th grader. Other times I am the 4th grader.
Iron Sharpens Iron either way.