tig rig

By scrappywelds (***)

Date 01-14-2011 02:11

dcen polarity

By 52lincoln (***)

Date 01-14-2011 02:53

man i gotta admit,i dont know what dcen is

By ctacker (****)

Date 01-14-2011 03:23

Direct Current Electrode Negative

By aevald

Date 01-14-2011 03:33

Hello 52lincoln, as the others mentioned, when the polarity is set correctly you will likely have a very nice, quiet, smooth arc coming off of the electrode end of your tig torch. If you get it wrong, the tungsten will appear to burn-up and ball on the end almost instantly(tungsten diameter and amperage might also play a part here, need to have a large enough diameter tungsten to handle a particular amperage setting). Pay attention to the type of tungsten as well. Pure tungsten will not work with your set-up. 2% thoriated is common, yet other types are possibly suggested based on a bit of radioactivity associated with the grinding dust that comes off of the thoriated tungsten as well as amperage handling of other types of tungsten. Check out the search function of the forum and you will find out a host of information to help you with starting techniques, settings, grind profiles for the end of the tungsten, selection of diameters for particular applications, and a lot of other information to help you to get the most out of a scratch start, air cooled tig rig. Even though scratch start tig is a relatively basic and simple tig application you can do many things to improve your quality, speed, and consistency. Good luck and keep us all posted. Hope some of this helps as well. Best regards, Allan

By TozziWelding (**)

Date 01-14-2011 13:10

DCEN= Electrode Negative

I have run this rig off everything from my old SA200 to my Trailblazer to an inverter in plants.

By Paladin (***)

Date 01-14-2011 13:11

Just so it is perfectly clear. The above comments are right but I'll try to say it another way.

Stick welding usually (few cases not) is done with the electrode on the positive terminal and the ground hooked up to the negative terminal. This is REVERSE POLARITY, direct current electrode negative (dcen).

On the SA 200, looking the control panel, the ground is on the left and the electrode lead is hooked to the right positive terminal.

TIG welding with DC current is STRAIGHT POLARITY, direct current electrode positive (dcep). So just hook the ground lead to the positive terminal and the torch lead to the negative terminal.

Floyd

By joe pirie (***)

Date 01-14-2011 13:56

No offense but in pretty sure your that stick welding on dc reverse is DCEP straight polarity is DCEN but
the way you described hookup on the machine is correct

By weldwade (***)

Date 01-14-2011 16:09

Floyd,
Reverse Polarity is DCEP (Direct Current Electrode Positive)
Straight Polarity is DCEN (Direct Current Electrode Negative)
You have explained how to properly hook up the "Tig Rig" otherwise.

By Paladin (***)

Date 01-14-2011 23:23

You guys are exactly right. I know that but looks like I can't think and type.

For the record: Reverse polarity dcep, straight polarity dcen.

There I think I got it this time. Sorry for any confusion.

Floyd

By Tommyjoking (****)

Date 01-15-2011 01:00 Edited 01-15-2011 01:03

LOL I always hated saying reverse and straight because it makes people get confuzed.....the proper way DCEP and DCEN eliminates that. But I do have an old shop machine that actually says "reverse" and "straight" on the control...I guess there is some history there.

By JeremyW83 (***)

Date 01-15-2011 01:43

i have gotten into some pretty heated arguments over straight and reverse polarity. It is a very confusing terminology.

By Superflux (****)

Date 01-15-2011 02:00 Edited 01-15-2011 02:20

This is the story told to me by my first welding instructor who learned to weld before WWI. He was in his late 70's when I attended Trade school in 1973.
In the "Dark Ages"/infancy of SMAW, Bare wire was dipped in varnish and various other simple homemade fluxes...these worked best on an electrode negative/positive ground. Common logic, even back at the turn of the 20th century, was to have a negative ground. So, welders were just as confused way back then. As manufacturers started developing fluxes through advanced chemistry, most were found to have better ductility and arc stability on Negative ground. Then Welders had to learn to "reverse" the method of hooking up leads.
The memory aid I was taught was the SENator and REPresentative one, where S(traight) E(lectrode) N(egative) and R(everse) E(lectrode) P(ositive).

By JMCInc

Date 01-15-2011 06:01

DC current flows from negative to positive. DCEP is reverse polarity because the current is coming back at you. The tungsten on a tig torch does not do well when it is on the receiving end of the current. As a previous poster stated, the electricity will erode the tungsten at a fast and furious rate. However, you can "shoot" the electricity out of the tungsten (DCEN, or straight polarity) all day long.