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  • #16
    Originally posted by davedarragh View Post
    Are you LA City and FEMA 353 Qualified too?

    Dave

    No, I'm not confused, I'm just wondering why someone from the most earthquake prone state on the planet could be so cynical?
    I am not in LA City so do not need nor have I ever been asked for a LA City documentation.

    FEMA I do follow all FEMA 353 standards wen called for.


    I don't understand where you are coming from with the question about my cynicism or seismic activity of my location?


    I am simply trying to point out that the question about "quality of weld"
    needs some parameters around it for it to have meaning.

    Comment


    • #17
      "Weld Quality"

      FATFAB: When someone asks about "Quality of a Weld," there's a difference between one that looks pretty (.025 MIG wire/C-25) and actual weld penetration and deposition. I referenced AWS D 1.8 pursuant to this anology.

      There have been many posts (seems lately) where some think that an under-sized machine can produce safe, quality welds, simply because they look "pretty." I realize the original post did not mention machine type, or wire size, nor was a prospective project mentioned.

      Your comment about a "kitchen chair" and the "Empire State Building" seemed cynical, as did your response of forum members who posted vague answers.

      It was not an attack on you or your character. As you do live in a very siesmically active area, I only assessed you could echo the importance of using the proper filler metal(s) for the right job.

      It behooves all of us to promote safety, whether it be a hobbiest or a pro. Familiarizng one's self in these standards gives the user the needed insight into the understanding of "quality welds."

      I would no more want to see a "kitchen chair" weld fail or a building crumble to the ground.

      If you feel slighted by my answers, I do apologize. It wasn't meant to be conveyed that way. Having said that, I think we can all agree, that a "quality weld" is much more than a "pretty bead."

      Dave
      "Bonne journe'e mes amis"

      Comment


      • #18
        Didn't mean to open up a can of worms,,,,all I was wondering was,,if you had a new peice of say, 1/4" flat mild steel,,,would a flux core wire give the same quality (strong) of weld as mig wire with 75/25 gas...would the weld be as strong. That is if a good weldor was doing the welding... Think I should have said earlier the key word was " AS STRONG "

        Comment


        • #19
          "1/4" Flat Stock"

          coop: Flux core would be much stronger. Even though many MIGs advertise welding capabilities exceeding 5/16," flux-core provides better penetration.

          There's really no "mystery" to flux-core. Think of it as a conventional welding rod turned inside out. Wire feed speeds are slower, and in some ways it can be "more forgiving."

          Once cleaned up (I used knot or cup brushes on an angle grinder), their appearance is fine.

          You didn't stir anything up with your question, maybe I was a little tired and grouchy (?) when I posted my answers. To those who may have been offended, I sincerely apologize.

          Dave
          "Bonne journe'e mes amis"

          Comment


          • #20
            Thanks Dave,that was the kind of answer I was looking for,,simple and to the point. I know that some will say there are no simple answers to the question, but that was what I was looking for.

            Thanks for the input...Mike

            Comment


            • #21
              Coop, in speaking to your original questions this is probably redundant and just restates what others said, but sometimes it helps to hear the same concepts expressed in different ways.

              First, my notion, and correction from the experts is welcome, is that the chief advantage of flux-core, no-gas welding is that it works outdoors, on tall buildings and bridges with the wind whipping around, where a shielding gas would be useless. A secondary advantage is that it avoids the handling and expense of shield gas. One disadvantage, it has seemed to me, is extra cleanup, and another is that with the smoke, it's harder to see the puddle. Flux-core wire can be found in very small diameters, but I don't see it as being as good as MIG for, say, autobody work, or chair legs. But flux-core wire takes less amperage for a given wire size than MIG, so when you are working at the upper end of your machine's output, using a flux-core wire will let you weld thicker metal than you could do with solid wire and gas. So there's another advantage.

              A problem for new welders with new wire-feed machines is that the MIG process makes it easy to lay down good-looking unsound welds. This wasn't true for earlier generations of welders because we had to develop more skill just to make stick-welds or gas-welds that looked even marginally acceptable, and by that point we might also have started to be aware that there were aspects other than appearance to consider. The problem with MIG for the new guy is getting full penetration consistently so that he can make good welds when he can't check the back side afterwards. Since flux-core wire penetrates better, it might save a new welder from his inexperience. And as the others said, you better know the limitations of your machine, and not try building trailer hitches with your 100A wire-feeder. Some new welders (and some old welders who should know better) are lazy about joint pre-cleaning and set-up, and flux-core wire might be a little more forgiving here, but why take a chance, do joint-prep right every time. Another aspect is wire quality; there is some pretty crappy wire coming in from who-knows-where, and on the other end there is triple vaccuum remelt steel used in the mega-buck wire. Among good quality wires there are dozens of formulations, as the other guys said, although your local supplier won't have it all on hand (mine sure doesn't).

              Weld a lot of test coupons, study 'em, bend-test 'em. I hope I'm not talking down to you here, I just got the impressions from your question that you are new to all this.

              Comment


              • #22
                Hey Smitty,,thanks for your reply. Not new to welding and I did know about it was better to use flux core outside or around a fan. All of my welding is done in my shop with a 210 amp welder and just never had a reason for using flux core. The subject came up and I knew I could find it out here........
                Thanks again...Mike

                Comment


                • #23
                  "Overlooked One Item"

                  coop: In all of these posts, none of us mentioned (for all to consider) when using flux-core wire (without shielding gas) polarity needs to be switched to DC-. With most all-in-one MIGs this necessitates physically switching the gun and work leads "under the lid."

                  I agree with seattle smitty's assessment of the progression in MIG machines in the past 10 years or so, that the machines are "dialed in" so close from the factory, that novices make "pretty" welds, though they may not necessarily be "sound welds."

                  2" x 1/8" flat sock 4" -6" long makes for "nice coupons."

                  Dave
                  "Bonne journe'e mes amis"

                  Comment


                  • #24
                    clarity

                    A Couple of things to keep in mind, not a complete list just a couple things.
                    1.Quality as defined by AWS D1.1 is to be compliant with the standard. Quality in the code is only used as a representation of discontinuity in relation to the code.
                    So quality is a subjective term-what are you comparing the result to? It will not be "perfect" no one can afford perfect. It is like trying to mathematically reach infinity.

                    2.To make a claim that flux cored wire is categorically better than solid wire is just wrong. Or to claim that AWS "knows it", sorry try again. Both wire types have prequalified status for a limited range of wires. Just to say that flux cored wire is prequalified is wrong, some are some aren't just like solid wires. A little time in the code book will reveal this to you. AWS as an organization will probably not claim to "know" anything, doing so places a stake in the ground and reduces the ability to respond.

                    3. As much as manufacturers would like you to think that they have the cure all wire they don't. It falls on your shoulders to make an informed choice as to which one to use. The informed part comes from doing some testing, and if you don't know how to do the testing then hire a CWI to guide you through the maze and it is a maze. The variability of all aspects of welding doesn't lend itself to an easy answer, as much as we all would like one.

                    4. Anyone can produce a weld that looks good but fails miserably if they are not in control of the process. I have been a welder for 16 years, a CWI for 5 years and a degreed welding engineer for 5 years and can walk out right now a lay down junk if I do not control it.

                    5.There are arc characteristics that are related specifically to the wire type be it solid or tubular and they have dramatic impact on penetration profile bead shape toe wetting etc. Learn the difference and you'll be way ahead.

                    6. 75/25 Argon CO2 will NEVER allow you to reach a spray transfer with solid wire. The CO2 is a reactive gas and therefore consumes some of the energy across the arc.It will only allow you to be in a short circuit mode even at higher voltages it is a gross (my opinion) globular transfer that will produce a lot of spatter in big chunks. A minimum of 80% argon is needed to smooth out the transfer and get the wire to neck when the ball is being pinched off. Try it and you'll see. The gas doesn't cost any more than 75/25 but does so much better. Gas type/mixture has a HUGE impact on the properties of the weld such as penetration depth, spatter control, transfer efficiency, mechanical properties including tensile strength, ductility, yield and the list goes on.

                    7. There is a lot more to understand than simply choosing a wire based on one or two criteria. If you don't know then it is good to learn the differences so the choices become easier. Not easy just easier. Every situation has something different than the last and should be considered.

                    Comment


                    • #25
                      coop,
                      While you have asked a good question, you can see that there is no real good answer for such a broad question. To give a good answer you would need to ask a more specific question.
                      Others have made the statement that one is a stronger weld than others, this is wrong. All 70 series electrode are created equal. All have a 70ksi tensile strength. Statements were made that FCAW-S (gas shielded) are better. What this may be eluding to is toughness. FCAW-S and E7018 are both electrodes that result in a more ductile (toughness)deposited weld metal. There were also statements about FCAW being a low hydrogen electrode. This is incorrect information as well. FCAW electrodes are available with lowhi properties, but so are others. It's just an additionally option.
                      I'm a QC manager at a structural steel fab shop and I utilize a few processes. It all depends on the application. I use FCAW-G (gas shielded), GMAW solid wire, GMAW metal core, and SAW (sub arc) it all depends on the application. Each one has it's place, a situation when it's properties make it the best option. When welding heavy section or long CJP welds I would lean toward SAW. If we have some out of position welding then FCAW-G would be a better option. When welding 3/16" material I would want to use GMAW solid wire. For flat CJP welds that require ultrasonic testing I would want to use GMAW metal core. For FEMA CJP welds I could use GMAW, SMAW or FCAW-G. SMAW will not have the same ability in regard to deposition rate, GMAW has the inherent difficulty with side wall fusion (especially at the root of material over 3/4"(not so much with metal core but it is still there)) so I would chose FCAW-G (due to lowhi requirements, deposition rate, and ease of use). All of these are 70 series electrode's. All have the same tensile strength.
                      "Religion is regarded by the common people as true, by the wise as false, and by the rulers as useful."

                      -- Seneca the Younger

                      Comment


                      • #26
                        Deleted message
                        Last edited by waltsuz; 01-28-2009, 02:04 PM.

                        Comment


                        • #27
                          Originally posted by davedarragh View Post
                          FATFAB:

                          If you feel slighted by my answers, I do apologize. It wasn't meant to be conveyed that way. Having said that, I think we can all agree, that a "quality weld" is much more than a "pretty bead."

                          Dave
                          No slighting perceived.

                          Quality of a weld can and is judged on so many levels. With out proper information regarding intended use, parent materials, filler materials, joint design and so on no one could ever say "this is always better than that". Pros and Cons exist in all processes and all process are a compromise of, speed, ease of use, cost of equipment, consumables and labor.

                          Knowledge in King. Experience is Key.

                          Comment


                          • #28
                            Originally posted by coop View Post
                            Didn't mean to open up a can of worms,,,,all I was wondering was,,if you had a new peice of say, 1/4" flat mild steel,,,would a flux core wire give the same quality (strong) of weld as mig wire with 75/25 gas...would the weld be as strong. That is if a good weldor was doing the welding... Think I should have said earlier the key word was " AS STRONG "
                            Again you ask a great question, with a vague reference to to a characteristic, that has many definitions or interpretations.

                            Strong: my dictionary has 30 plus definitions. What one are you using?


                            In answer tho I would say "yes" if......... and the list for "If" is huge and varied. All things being equal both welds would pull (tensile) at a a number higher than the parent material (assumes A36 parent material) Charpy impacting would/could vary greatly depending on fillers used(within each process)

                            Comment


                            • #29
                              Originally posted by hogan View Post
                              coop,
                              While you have asked a good question, you can see that there is no real good answer for such a broad question. To give a good answer you would need to ask a more specific question.
                              Others have made the statement that one is a stronger weld than others, this is wrong. All 70 series electrode are created equal. All have a 70ksi tensile strength. Statements were made that FCAW-S (gas shielded) are better. What this may be eluding to is toughness. FCAW-S and E7018 are both electrodes that result in a more ductile (toughness)deposited weld metal. There were also statements about FCAW being a low hydrogen electrode. This is incorrect information as well. FCAW electrodes are available with lowhi properties, but so are others. It's just an additionally option.
                              I'm a QC manager at a structural steel fab shop and I utilize a few processes. It all depends on the application. I use FCAW-G (gas shielded), GMAW solid wire, GMAW metal core, and SAW (sub arc) it all depends on the application. Each one has it's place, a situation when it's properties make it the best option. When welding heavy section or long CJP welds I would lean toward SAW. If we have some out of position welding then FCAW-G would be a better option. When welding 3/16" material I would want to use GMAW solid wire. For flat CJP welds that require ultrasonic testing I would want to use GMAW metal core. For FEMA CJP welds I could use GMAW, SMAW or FCAW-G. SMAW will not have the same ability in regard to deposition rate, GMAW has the inherent difficulty with side wall fusion (especially at the root of material over 3/4"(not so much with metal core but it is still there)) so I would chose FCAW-G (due to lowhi requirements, deposition rate, and ease of use). All of these are 70 series electrode's. All have the same tensile strength.
                              Hogan thank you!

                              I could have never said it better.

                              Coop Great questions provids us all to more clearly understand "welding"

                              Someone in this thread mentioned testing your work. I have said this many times in other posts. No mater haw diligently one follows a procedure (read recipe for making a weld) until you destroy examine or otherwise dig inside a weld you made "you" wont know what exists inside or it's quality.


                              All welds have discontinuities (read imperfections).

                              Comment


                              • #30
                                Glad to help. Information is best when shared.
                                "Religion is regarded by the common people as true, by the wise as false, and by the rulers as useful."

                                -- Seneca the Younger

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