[AKweldshop]

I have been told by a very professional welder , when welding out of position ,DC- works better with 7018, I can't remenber what amperage he would use, colder or hotter, He was always running back and forth, changing amps and polarity, but it helped make more concave welds ,which is what you want , I've always used DC+ for 7018 out of position welding , and it works good for me , what do you guys think thanks John

[plantwelder]

I've tried it, but it seems you need to jack up the current to get any penetration. By and large if you stick to the rod manufacturers guidance, you get the best results.

[jwmacawful]

I've tried it, but it seems you need to jack up the current to get any penetration. By and large if you stick to the rod manufacturers guidance, you get the best results.

professional welder here has to agree that you can't go wrong following mfgr's instructions and recommendations. i'll bet the job's welding inspector would be of the same opinion. another fairly common but prohibited practice is running a downhand 7018 before following it with a vertical up weld on a fillet joint. the thin down pass fills in the corner and makes the following pass easier. cbi use to give a low hydrogen downhand test for tankwork.

[plantwelder]

I've tried it, but it seems you need to jack up the current to get any penetration. By and large if you stick to the rod manufacturers guidance, you get the best results.

professional welder here has to agree that you can't go wrong following mfgr's instructions and recommendations. i'll bet the job's welding inspector would be of the same opinion. another fairly common but prohibited practice is running a downhand 7018 before following it with a vertical up weld on a fillet joint. the thin down pass fills in the corner and makes the following pass easier. cbi use to give a low hydrogen downhand test for tankwork.

Yes, but are you "very" professional?

[noddybrian]

It's funny - but in the UK virtually all 7018 are dc + or - AND AC ! ( provided its 70 volts ocv or higher ) I never tried vertical down as the slag is a slow freeze mess trying to do it - but several WPS called for electrode negative on the root run of single sided groove welds - it can be done without - but a remote amp control makes life so much better - I just wish it was easier to source the machine connectors & pin out wiring - manufacturers are a nightmare for changing them model to model & charging silly money for a small tin box with a potentiometer in.

[jwmacawful]

I've tried it, but it seems you need to jack up the current to get any penetration. By and large if you stick to the rod manufacturers guidance, you get the best results.

professional welder here has to agree that you can't go wrong following mfgr's instructions and recommendations. i'll bet the job's welding inspector would be of the same opinion. another fairly common but prohibited practice is running a downhand 7018 before following it with a vertical up weld on a fillet joint. the thin down pass fills in the corner and makes the following pass easier. cbi use to give a low hydrogen downhand test for tankwork.

Yes, but are you "very" professional?

only during a full moon and a high tide when it falls on a leap year.

[jwmacawful]

It's funny - but in the UK virtually all 7018 are dc + or - AND AC ! ( provided its 70 volts ocv or higher ) I never tried vertical down as the slag is a slow freeze mess trying to do it - but several WPS called for electrode negative on the root run of single sided groove welds - it can be done without - but a remote amp control makes life so much better - I just wish it was easier to source the machine connectors & pin out wiring - manufacturers are a nightmare for changing them model to model & charging silly money for a small tin box with a potentiometer in.

i believe miller has a new wireless remote amp control.

[Ranger]

I have been told by a very professional welder , when welding out of position ,DC- works better with 7018 , helps make more concave welds ,which is what you want , I've always used DC+ for 7018 out of position welding , and it works good for me , what do you guys think thanks John

When someone tells you can do something not normal then ask them to show you how and get them to explain it to you how it works and why ...
But also remenber just cause someone can do something does not mean you can and it will turn out good .....

[AKweldshop]

This Professional Welder said its really a help in 2g horizontal v grooves and overhead lap joints , by really pushing the metal in there and making a flatter weld most of the other guys, now matter the joint ,always ran DC+ with 7018 for everything and do a really good job with it , but this guy really made flat welds in the overhead position , I've tried running 7018 on DC- and I've always mixed results ,erratic arc / hard to control rod etc, seems weird to me , but I don't know, do you guys ever use DC- for "ANY" 7018 joints thanks John

[Otto Nobedder]

They actually make a rod called 7018AC, that might function well on DCEN in these applications. I've never tried.

I've never tried a 7018 root on pipe, either, but I've done a ton of plate welds in all positions using 7018 open root, ALWAYS DCEP as the box recommends. I've never had the opportunity to see the back-side of these welds, as they were wall closures, with hundreds of plug-weld in between.

All my carbon pipe welds have been either 6010 root or TIG root.

Steve S

[weldin mike 27]

Hey,

During a similar discussion on a facebook group, pipe welders chimed in and said they swear by - (or + not sure which ) on a root run then swap for the rest, not sure what the inspectors would say about the deviation from procedure though.

Mick

[plantwelder]

As Noddybrian says, in the UK 7018's tend to be for DCEP, DCEP or AC. That said, on DCEN you seem to need quite a step up in current, and DCEN isn't much use for anything other than flat or h-v fillet. On AC they' make a lot of spatter. Can't beat DCEP.

[jwmacawful]

This Professional Welder said its really a help in 2g horizontal v grooves and overhead lap joints , by really pushing the metal in there and making a flatter weld most of the other guys, now matter the joint ,always ran DC+ with 7018 for everything and do a really good job with it , but this guy really made flat welds in the overhead position , I've tried running 7018 on DC- and I've always mixed results ,erratic arc / hard to control rod etc , seems weird to me , but I don't know , do you guys ever use DC- for any 7018 joints thanks John

ak- i for one have never used dc straight polarity for 7018. that's my story and i'm sticking to it.

[AKweldshop]

I agree, DC+ is all I use , I was just asking if you guys use DC- and if it works know hard feelings , thanks John

[Nils]

Most all SMAW welding is done DCEP while running DC current. The reason for this is the flux coating needs to vaporize as quickly as possible for proper shielding. With the current running from the work into the electrode this is accomplished. Why a welder would reverse this could be for an area that is closed in and a deeper penetration and puddle sticking is desired. I have never encountered the need, but maybe someday.

[Tombstone]

The only time DC- works best is when it's used with 6013 on thin sheet metal. Before mig welding was the norm for sheet metal, 6013 was designed specifically to run on DC-

[Svetsare]

I have used dc- on pipe roots, when welding 7018 on so big cap that you cant normally weld it.
If I normally i can weld 2,5mm-3mm cap with dcep,(depending how thick material I am welding of course) then when I change to dc- I can weld something like 4-5 mm cap.
There is a huge difference. You can weld x-ray quality with dc-.

But usually I stick with dcep, it burns much more smoothly.

[AKweldshop]

Hey thanks I'll give it a try....
John

I have used dc- on pipe roots, when welding 7018 on so big cap that you cant normally weld it.
If I normally i can weld 2,5mm-3mm cap with dcep,(depending how thick material I am welding of course) then when I change to dc- I can weld something like 4-5 mm cap.
There is a huge difference. You can weld x-ray quality with dc-.

But usually I stick with dcep, it burns much more smoothly.

[Tombstone]

I have used dc- on pipe roots, when welding 7018 on so big cap that you cant normally weld it.
If I normally i can weld 2,5mm-3mm cap with dcep,(depending how thick material I am welding of course) then when I change to dc- I can weld something like 4-5 mm cap.
There is a huge difference. You can weld x-ray quality with dc-.

But usually I stick with dcep, it burns much more smoothly.

Based on what you said, I think you have your "wires crossed," literally. DC- produces a much shallower weld bead than DC+. A friend of mine for years always thought he was running DC+ on his buzz box! until one day I noticed he had his stinger and ground clamp swapped on the wrong lead. So when his machine was set on either DC "+" or "-" he was actually running the opposite polarity. When we compared my discovery, coupled with his (backwards) connections and the owner's manual wiring diagram, we fixed it. He always wondered why he was able to lay down thicker welds when the machine was set to "DC-". Now he doesn't have that problem any more.

[MinnesotaDave]

From Miller (for SMAW in general):

image.jpg (31.43 KiB) Viewed 1470 times

Other manufacturers list the same information.
Naturally an electrode would have to be rated to function in the desired polarity for this information to be of any use.

[Svetsare]

I have used dc- on pipe roots, when welding 7018 on so big cap that you cant normally weld it.
If I normally i can weld 2,5mm-3mm cap with dcep,(depending how thick material I am welding of course) then when I change to dc- I can weld something like 4-5 mm cap.
There is a huge difference. You can weld x-ray quality with dc-.

But usually I stick with dcep, it burns much more smoothly.

Based on what you said, I think you have your "wires crossed," literally. DC- produces a much shallower weld bead than DC+. A friend of mine for years always thought he was running DC+ on his buzz box! until one day I noticed he had his stinger and ground clamp swapped on the wrong lead. So when his machine was set on either DC "+" or "-" he was actually running the opposite polarity. When we compared my discovery, coupled with his (backwards) connections and the owner's manual wiring diagram, we fixed it. He always wondered why he was able to lay down thicker welds when the machine was set to "DC-". Now he doesn't have that problem any more.

Hmm, no I dont think so. I know what polarity I am welding. It is so much different when you are welding with electrode negative. I travel a lot and weld with different machines so this aint a thing that works only with my own welding machine. And many welders around here uses this same trick, when they got a way too big cap to weld with normally electrode positive.
I really shouldnt give advices here, becouse stick welding in here is so much different then it is in states..

[Tombstone]

I really shouldnt give advices here, becouse stick welding in here is so much different then it is in states..

Svetsare, not trying to start a war here or anything, honest. However, physics including electrical theory is the same here as it is on the other side of the pond. GTS (Google That Stuff) about welding polarity and penetration and you will see that what I've said is correct about AC, DC+ and DC-. MinnDave posted a chart that states the same thing I've been telling you. You will find the same info in all publications related to this subject.

Maybe DC- does fill a large gap better without making a deep keyhole or something depending on the electrode you're using, I just don't know. I'll have to experiment with that idea myself. I always use DC+ and sometimes AC. Rarely do I use DC- when mig has replaced my thin metal welding requirements.

For thin metals, DC- is the way to go for stick welding and It's best with 6013's in particular. Try it out yourself and you'll see what I'm talking about. Try a scrap piece of 10ga (3.5mm) sheet metal with a 3/32" (2.4mm) or even better, 5/64" (2.0mm) electrode using 6013. Try both DC+ and DC- polarities and I guarantee that you will find that DC- gives you more control with less (if not "any") burn-through.

I don't know how you guys do it, but I do know there is one Irishman on another welding website that welds pipe with 6013! He's posted lots of pictures of it I don't understand that, but he does it nicely too. Although I highly question the integrity and strength of that pipe weld using 6013. It would never pass any "code" requirement here in the States, but he says "they" use it routinely in Europe (or at least Ireland IIRC).

[AKweldshop]

I really shouldnt give advices here, becouse stick welding in here is so much different then it is in states..

Svetsare, not trying to start a war here or anything, honest. However, physics including electrical theory is the same here as it is on the other side of the pond. GTS (Google That Stuff) about welding polarity and penetration and you will see that what I've said is correct about AC, DC+ and DC-. MinnDave posted a chart that states the same thing I've been telling you. You will find the same info in all publications related to this subject.

Maybe DC- does fill a large gap better without making a deep keyhole or something depending on the electrode you're using, I just don't know. I'll have to experiment with that idea myself. I always use DC+ and sometimes AC. Rarely do I use DC- when mig has replaced my thin metal welding requirements.

For thin metals, DC- is the way to go for stick welding and It's best with 6013's in particular. Try it out yourself and you'll see what I'm talking about. Try a scrap piece of 10ga (3.5mm) sheet metal with a 3/32" (2.4mm) or even better, 5/64" (2.0mm) electrode using 6013. Try both DC+ and DC- polarities and I guarantee that you will find that DC- gives you more control with less (if not "any") burn-through.

I don't know how you guys do it, but I do know there is one Irishman on another welding website that welds pipe with 6013! He's posted lots of pictures of it I don't understand that, but he does it nicely too. Although I highly question the integrity and strength of that pipe weld using 6013. It would never pass any "code" requirement here in the States, but he says "they" use it routinely in Europe (or at least Ireland IIRC).

Hey Tombstone, here's your link
http://weldingweb.com/showthread.php?19742-6013-dcen

[Tombstone]

AK, Yup that's the one! Pipe fitter makes some of his 6013's look like my tig welding! Anyway, he or anybody else would be fired here in the states if he was caught using 6013 on pressured pipe. The welds look nice, but it would NEVER EVER hold up to a 5P root plus 7018 cap There's a reason 6010 and 7018 are used with DC+ and not DC- for code work and critical weld joints here in the USA and Canada.

Maybe if I was welding gum ball machine "pipe" or pipe for umbrellas and such, 6013 on DC- would be the best choice without mig or tig.

[AKweldshop]

Those welds look good, good root, good wash in, why are you saying they won't stand up to 6010/7018????
John