Stick Welding Polarity - which info is wrong.

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Talking stick welding here and electrode polarity. Everything I've read has said with electrode +ve you get max. penetration, and with electrode negative you get less penetration.Here in Australia I have a book - Metal Fabrication Course - Apprentice Reference Notes. On page 331 it says the following: "When a welding current flows across an arc gap 2/3 of the heat of the arc is generated on the side (pole) which is being bombarded by the electrons". Then a bit further down: "......the greater amount of heat can be concentrated on the parent metal to increase to increase the depth of penetration, by making the parent metal positive and the electrode negative. Alternatively if greater deposition rate is important the parent metal should be connected negative and the electrode positive, the greater amount of heat increasing burn off rate".This is completely opposite to what I have "learned" so far. Which one is wrong ??Cheers,Keith.
Reply:I only know stick welding, but I believe it's different for different processes, so that may be one source of the conflict. I'm sure others will chime in with more info.See this thread for more info: http://www.hobartwelders.com/weldtal...P-GET-IT-RIGHT!
Reply:Just found an answer from a post by DocWilson.This can be a confusing issue to a lot of people. "Welder" is 100% correct from a strictly electrophysics standpoint. DCEN puts more of the heat into the work and DCEP concentrates the heat onto the electrode. The problem arises in the fact that this only holds true if you are using GTAW or are stick welding with a bare electrode. It does not take into account that penetration is greatly influenced by the plasma gases created by different flux coatings. Markopolo and DDA52 are correct about 95% of the time when they state that in SMAW, DCEP gives deeper penetration. You always have to go by what the manufacturer says concerning the use and characteristics of a particular electrode. Most reverse polarity rods are designed to have the metal core melt faster that the flux coating. This forms a cup like crater at the end of the electrode and the theory is that the molten metal and positive ions created in the arc plasma shoot across the arc with such force and attraction for the negatively charged workpiece that this is what causes you to get a more aggresive arc and deeper penetration. Again, it depends on the flux coating, but most of the time in SMAW, reverse polarity will give you deeper penetration. If you are TIG welding, then you will want to go with "Welder", and get your deeper penetration with DCEN. By the way, it is that same bombardment of positively charged ions in the plasma, being attracted to the negativlely charged work, that breaks up the oxides when using AC GTAW to weld aluminum.
Reply:More info:This is because of the non-consumable electrode and inert gas vs consumable electrode and active gas or fluxGTAW = non consumable electrode with inert gasDCEN = 30% heat on electrode 70% on workDCEP = 70% heat on electrode 30% on workSMAW, GMAW, or FCAW = consumable electrode with active gas and or fluxDCEN = 70% heat on electrode 30% on workDCEP = 30% heat on electrode 70% on work
Reply:Yeah... heard this before, been discussed before too.This heat deposition thing is true for TIG with a non-consumable electrode; tungsten electrode negative (1/3rd the heat) and the work piece positive (2/3rd the heat).For stick (consumable electrode), this +ve / -ve heat thing and penetration does not really apply; as the electrode manufacturer's say...it's more a question of the coating on the electrode that determines which polarity to run and the resulting penetration.Rick V 1 Airco Heliwelder 3A/DDR3 CTC 70/90 amp Stick/Tig Inverters in Parallel1 Lincoln MIG PAK 151 Oxy-Acet
Reply:Hmmmmm, you need a chart to see which polarity to use in which circumstance....we don't have that problem with a plasma welder as it all happens in the torch nozzle, pure heat at 8,000 deg C.Ian.
Reply:There is a L-O-N-G discussion on this very subject on the AWS forum:http://www.aws.org/cgi-bin/mwf/topic_show.pl?tid=31375As you can see, this subject confuses even the Big Brains over there. JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:mancavedweller  -  Are you in the Opal-Region, or live in your shop?I would pass on an in depth understanding of electron-flow theory; and master the application of each type of rod.In the US, brand-names mean virtually nothing [except for highly specialized applications].  The AWS  -  American Welding Society,E-xxxx is the tell-all.  Its a standardized specification  -  tensile strength, position, and polarity/coating.I'm not familiar with Australasian Welding Designates, but most certainly there is a cross-reference.First, experiment and master every type of rod in common usage for itsdesigned application; then you will be able to see, and better understand polarity-theory.Opus
Reply:Thanks everyone.Opus I don't live in my shop but once I get it more organised I might consider the idea  Don't think there's many opals in the Melbourne area, I'd put my little excavator to better use if there was It makes sense now, some of the reports I've heard about a rod being used on DC- polarity and it seemed to make the arc more "angry". Never knew about the flux having such a big impact on the DC+ or DC- thing. Damn these forums are good.Cheers,Keith
Reply:I just use the rod as the manf. instructions say on the box.Also much of the weld metal deposited from the iron powder coated rods is supplied from the flux coating, in addition to the deposit from the core,  which applies to all the xxx4 and xxx8 series rods.  That is why a 3/32" 7018 rod will deposit approximately the same amount of weld as a 1/8" 6010 rod.  Presumably the extra heat of dcrp is needed to melt the iron powder in the flux."The reason we are here is that we are not all there"SA 200Idealarc TM 300 300MM 200MM 25130a SpoolgunPrecision Tig 375Invertec V350 ProSC-32 CS 12 Wire FeederOxweld/Purox O/AArcAirHypertherm Powermax 85LN25