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Poland308 wrote:It's more subtle. These same principles also apply to tig welding. Reversing polarity from electrode neg, to electrode positive causes the heat to be focused into the tungsten more than the base metal.
Which for TIG welding is not beneficial of course. :)
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MinnesotaDave wrote:
Poland308 wrote:It's more subtle. These same principles also apply to tig welding. Reversing polarity from electrode neg, to electrode positive causes the heat to be focused into the tungsten more than the base metal.
Which for TIG welding is not beneficial of course. :)
Then you have to increase tungsten sizes or drop amperages to avoid melting your tungsten.
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Farmwelding wrote:
MinnesotaDave wrote:
Poland308 wrote:It's more subtle. These same principles also apply to tig welding. Reversing polarity from electrode neg, to electrode positive causes the heat to be focused into the tungsten more than the base metal.
Which for TIG welding is not beneficial of course. :)
Then you have to increase tungsten sizes or drop amperages to avoid melting your tungsten.
The benefit is not there, very large tungsten is required to weld at low amps.
It works for thin aluminum, I've tried it, but isn't very practical.
Dave J.

Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~

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olek
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After much reading and exchanges , I got that stick welding DCEN allow a quieter and more manageable arc so it is choosed by some for the first root pass (up to some thickness of metal certainly)
Also with thin gauges DCEN is used up to ga13 for instance, then with thicker steel it does not allow good enough penetration.
It makes root pass easier ,less risk of opening a large key hole better management of arc blow, etc.

That is about all I wanted to understand, there may be more subtleties depending of types of coating as different protective gas can be created, but I think I have my answers for the moment.

The shape is still flatter with DCEP, larger than with straight polarity. The names used as "reverse polarity" that mean the opposite for 6013 and 7018 is a big help to obtain much confusion ;)

Best regards, and thanks all for your generous help.
Last edited by olek on Sun Jun 11, 2017 7:16 am, edited 1 time in total.
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Poland308 wrote:Resistance is your air gap. Or arc length.
https://en.m.wikipedia.org/wiki/Electroplating

Electron flow plays a part in deposition rates.
Is 'R' something you have in mind when welding, for instance modulating your arc lenght you know that you will have a certain effect in metallurgy ? I do not figure that very well yet, for instance I see I create more heat if I enlarge a hair the arc, but what happens when the arc is very short I don't know out that it is good to have a short but tense arc .
Is the arc somewhat tight lor "hard" when very short ? Tension is at its hughest then ? Sorry for the question see that is not yet totally clear even if it is basics.

For instance I think that "manual automatic" (dragging without much pull motion ) allow to use a strong amp, as it is at its lowest when dragging ...
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Keeping your arc length short is important. I don't ever think about the actual resistance it's creating. I can't think of any good things that happen when your arc is long. It's wasted energy, your machine has to run harder just to maintain the arc. You already noticed the heat increase you get. It's also possible to get it long enough that you don't get proper gas shielding. Undercut, loss of control or arc wander. I'm not sure about the metallurgy part other than that it has some effect mostly from the poor shielding, and a diferance in the metal structure as it's deposited.
I have more questions than answers

Josh
olek
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Hello

back to topic, I was lucky today to have a feel of the difference depending of polarity

on certain metals or may be only on thin or moderately thin, DCEN will penetrate better because of the sharper shape of the arc plus fused metal

the documents provided by the electrodes makers are intended to professionals , I suppose you weld with stronger electrodes than 1/8 and mostly on thick metal, I did see the guide from Lincoln : tables show thick electrodes and very high Amp.

as I see it DCEP became necessary then , to have adequate penetration, hence what say LINCOLN, ESAB, and others

so this is not contradictory in the end, I think,

still DCEN helps by providing a quieter arc and puddle for the type of weld I may have to do

Regards
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olek wrote:Hello

back to topic, I was lucky today to have a feel of the difference depending of polarity

on certain metals or may be only on thin or moderately thin, DCEN will penetrate better because of the sharper shape of the arc plus fused metal

the documents provided by the electrodes makers are intended to professionals , I suppose you weld with stronger electrodes than 1/8 and mostly on thick metal, I did see the guide from Lincoln : tables show thick electrodes and very high Amp.

as I see it DCEP became necessary then , to have adequate penetration, hence what say LINCOLN, ESAB, and others

so this is not contradictory in the end, I think,

still DCEN helps by providing a quieter arc and puddle for the type of weld I may have to do

Regards
You're overthinking this.
You want less penetration on thin metal, that's why the use of DCEN when needed.
You generally want more penetration when dealing with thicker metal, so use DCEP, or don't, it's up to you in the end. :)
Dave J.

Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~

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olek
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Yes , Dave, as a "virtual welder" ,without instructor, I overthink before going real ;)
that helps in the end to analyse my mistakes better, I think

the shape of the heat is supposedly different. More sharp in straight polarity. It may be better then for thinner metal as it is more difficult to burn thru .

DCEN is used here very often for root pass to have a neater job more easily no enlarged key hole etc

I try to find reasons when there are contradictions (some manual state that the dcen is deeper, but with no mention of electrode size and polarite this is worthless)

So it helps but then may be there is something relative to the size of the electrode that make some transfer mode more efficient.

I clearly did see dcep refusing to weld , sliding on the surface of the metal even on a precedent bead .

It may be well more quality vs deepness but the heat shape is still sharper. Regards
Last edited by olek on Sat Jun 24, 2017 10:02 am, edited 2 times in total.
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olek wrote:Yes , Dsve, as a "virtual welder" , I overthink before going real ;)

What are the most common size of your electrodes? (Is my thought about big electrodes for profesdional welders true ?)

helped me .. the shape of the heat is different. More sharp in straight polarity. It may be better then for thinner metal as it is more difficult to burn thru .

DCEN is used here very often for root pass to have a neater job more easily no enlarged key hole etc

I try to find reasons when there are contradictions (some manual state that the dcen is deeper, but with no mention of electrode size and polarite this is worthless)

So it helps but then may be there is something relative to the size of the electrode that make some transfer mode more efficient.

I clearly did see dcep refusing to weld , sliding on the surface of the metal even on a precedent bead .

It may be well more quality vs deepness but the heat shape is still sharper. Regards
My opinion is you may not be proficient enough to know what you are seeing.
If you can't weld on DCEP then you need to practice more, type less - lol :)
Dave J.

Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~

Syncro 350
Invertec v250-s
Thermal Arc 161 and 300
MM210
Dialarc
Tried being normal once, didn't take....I think it was a Tuesday.
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