DCEP versus DCEN stick welding

[dom14]

Hey Guys,

I'm wondering what's your experience with the above.

I'm about to weld a bung onto a pipe using arc(stick) welding(an inverter welder).
I already made the hole on the pipe.

What is the best way to go about it?!!
Pipe is a 1mm-2mm thick whereas the bung is pretty thick.
I'm thinking of 2mm or 2.5mm rods.
Should I use DCEP(electrode positive) or DCEN(electrode negative) to get a good weld without blowing a hole through the pipe or creating a bad weld with small holes/gaps??!
What is the recommended amp range?
What is the recommended rod size?

Thanx

[dom14]

I found below thread is pretty useful.

http://www.tractorbynet.com/forums/w...ve-ground.html

Explanation about the formation of lightening is pretty interesting.

[dom14]

And this,
http://www.millerwelds.com/resources...trode-negative

[GQtdauto]

Because of the thickness of pipe I'm assuming its exhaust , if you shape the bung to suit the pipe and keep hole size well under the circumference of bung you will probably still blow a hole in it unless your very skilled at arc welding .
Reversing polarity gives you more heat at electrode or more heat on the work surface dc neg or dc pos , to be honest it's been that long ago and after years of pain drugs I can't remember which is which but I can tell you arc would be my last choice for this job .
Either Mig , Tig or oxy would be my preference depending on what type of metal it is .
They do make a smaller electrode than 2.5 mm or at least they did 20 years ago .
If using 2.5 mm and you're going to give it a go start at lowest amps suggested and concentrate most of the heat on the thicker material keeping a short arc gap .

[PeeBee]

Dom, I am firmly seeing you as a total do-it-yourselfer, and I applaud you for that, but whats it going to cost to get the bung welded in at an exhaust place, $20??? Sometimes its best left to the guys who do this day in day out. They are familiar with the materials and the settings and style of welding. I can weld, MIG/TIG/ARC?Gas, but am in the novice class, so when there is a critical or tricky task, I leave it to the tradies to bring it home. I think this is really one of those examples as there are a number of variables you are asking to get answers on, and any one could end in tears if not correct. I hope you take this in the 'right light' it is offered.

[GQtdauto]

Well said , unless he has a bit of scrap lying around to practice on , which even I do sometimes , get someone with the right equipment .

[dom14]

Dom, I am firmly seeing you as a total do-it-yourselfer, and I applaud you for that, but whats it going to cost to get the bung welded in at an exhaust place, $20??? Sometimes its best left to the guys who do this day in day out. They are familiar with the materials and the settings and style of welding. I can weld, MIG/TIG/ARC?Gas, but am in the novice class, so when there is a critical or tricky task, I leave it to the tradies to bring it home. I think this is really one of those examples as there are a number of variables you are asking to get answers on, and any one could end in tears if not correct. I hope you take this in the 'right light' it is offered.

Hi Phil,
Thanx mate.
My MIG welder is out of action atm, hence the reason I'm going to stick welding.
I've done thin metal stick welding in the past(muffler), but basically learnt by experimenting.
You're right, it's not about the money, but me gaining some experience of performing tricky welds with less than perfect gear for the particular
welding task, hence the reason for my DIY.
I'm pretty sure I can manage this weld per day, but it generally comes out bit "gooey" looking due to it being arc welding, instead of MIG welding.

I've seen a guy welding two razor blades with perfect looking beads with a stick welder(in the internet), but indicated it's also from the particular type of welding rod he used, in addition to skill.

Thanx for the tips, but I'm still going to be adamant and DIY it and cry if I stuff it up.

Cheers

[dom14]

Well said , unless he has a bit of scrap lying around to practice on , which even I do sometimes , get someone with the right equipment .

I do have scrap(I'm a collector ) and have been practicing the "art" of thin metal stick welding. But, my welds still look ugly as hell.
I'm a long way to go, in terms of making them look nicer.

Cheers

[GQtdauto]

If you have an inverter welder and reverse the electrode and earth lead around you should get more heat off the job but your electrode will go red fairly quick , just keep changing them over , from memory you want to be well under 65 amp but on an inverter you won't know or be able to set it for that so practice on some scrap .
Keep arc gap to about 3 mm , rod about 45 degree angle to job and just a bit less in direction of weld , heating up electrode in an oven and using them hot may make them easier to start .

[threedogs]

do like my mate does if Im not around , stop ,start, stop ,start ,grind and repeat
you'll get it done in the end lol