Different welding processes require different current types. If you select the wrong current type for your process, the results will be subpar. It is usually pretty easy to know when you’re running the wrong polarity. The welds will look awful and you’ll know something has to change.
TIG welding on steel will require a negative polarity – in which case the torch has a negative current flowing into it, and the ground clamp has a positive flow.
Processes like stick welding require a different polarity type, which we’ll get into below.
Positive Polarity (DCEP) #1 Choice
Stick electrodes are generally run with a positive polarity (DCEP). With this setup, your electrode holder (stinger) has a positive current flowing to the stick electrode (also just called a “rod”). Your ground lead will be attached to the negative terminal of your machine.
This positive stick polarity will work with most rods when welding mild steel and even stainless steel. Once you attach your leads this way, you usually won’t have to change them.
As you can see on the Bobcat above, the negative terminal is on the far left. The positive terminal is on the far right.
Some stick machines may have these switched around, but they are always labeled. Even smaller entry level machines will make it clear which terminal is which.
Some machines and manuals may refer to the negative terminal as the “work” terminal. This “work” terminology simply means that it is where your ground clamp lead should go.
So, for a majority of stick welding, Positive polarity (DCEP) is the best route. Most rods are designed with this polarity in mind, and that won’t change anytime soon.
AC Polarity (Alternating Current)
Some stick welding machines will have an AC current. This “alternating current” is constantly switching between positive polarity and negative polarity.
Older Lincoln Buzzboxes often have AC as a power supply. Some stick machines may have an AC setting in addition to their DC settings.
While most stick rods are meant to be burnt on DC polarity, some rods do well with an AC current.
Rods like 6011’s and 6013’s do great on an AC current. They run best on it and are designed with AC parameters in mind.
6013 rods offer medium penetration and are great for welding thinner steels without much warping. Running these rods is best done on an AC current. Their heat input is manageable and it tends to bend and warp metals much less than other processes.
6011 rods offer very deep penetration, and can burn through rust and even light paint. These 6011’s are the AC version of the popular 6010 rod. For root passes and heavy duty applications, 6011 electrodes are worth a try.
So if you end up with an old AC stick machine, don’t worry – there are still some awesome rods that you can use with it!
Negative Polarity (DCEN)
While it is uncommon, it is possible to run negative polarity (DCEN) while stick welding. It generally produces less penetration, and the rods tend to burn faster. It is worth trying out if you’re welding on very thin steel – but it isn’t the prettiest.
Stick welding with negative polarity is definitely not common practice. Many welders go their whole careers without trying it out. However, if you want to test it out then go for it – It will not damage your machine.
Featured image credit: Oleksandr Panasovskyi, UA