Dual-shield FCAW question

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Hi WeldingWeb,I have a question about dual-shield flux core welding.  What is the best method of welding over very uneven terrain?  Think repairing completely butchered welds with tons of porosity, stubborn slag, holes, crevaces, etc.  I know that ideally, I should just gouge or grind it all down, but is there a way to do this without pre-weld preparation aside from some wire-wheeling?All answers and opinions are much appreciated.ThanksAspiring Top-Notch WeldorLooking for work/experience in Eastern Massachussetts
Reply:Grind em out. At the end of the day you can paint **** gold but it's still ****.
Reply:Weld it right the 1st time and you don't have to grind it out to redo it.The answer is no. You have to get rid of the bad weld 1st before you can repair it properly..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:If you try to weld over the mess with dual shield you are going to make a bigger mess.
Reply:if you want a sound weld as your finished product you're going to have to remove all the porosity and crap underneath before any kind of welding can commence.i.u.o.e. # 15queens, ny and sunny fla
Reply:Gouge or grind out any old welds then re-weld, but SOMETIMES its easier to cut out a new section and build a new part than re-weld something.Lincoln pro core 125 14''chop saw7 inch grinder,2-4.5 inch grinders,electric die grinder.Half inch drillAnd alot of hand tools
Reply:Carbon arc it out and start overDisclaimer; "I am just an a$$hole welder, don't take it personally ."
Reply:take it back down to the base and start overVantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:I agree with every one, but if you are going to try and weld over with out any prep, I would use a stick rod. that would be your best chance at getting it to work. If it was me I would grind it out and start over.Esab 253 mig welderHobart 210 mvp w/ C25 gasmiller 225 a/c stick welderO/A torchHF 40 amp plasma cutter
Reply:X3 or 4!Grind out all of the crap. Align your pieces properly and weld carefully.My preference is GMAW (MIG) since the flux starts as as gas and stays that way as the weld cools.Be wary of The Numbers: Figures don't lie,. but liars can figure.Welders:2008 Lincoln 140 GMAW&FCAW2012 HF 165 'toy' GTAW&SMAW1970's Cobbled together O/A
Reply:When in doubt Grind it out!
Reply:I am in the same boat now on a repair job. Grind it clean and redo.Except for the grinding,, I like when people do shoddy work, keeps my shop busy!!!TOOLS AND TOYSSMAW Mid States Inc. "MISSING LINK" 10-150 AMP Buzzer circa 1945ishSMAW Magic Wand 40-60 AMP Suitcase Buzzer circa 1939ishGMAW Hobart 210 IronmanOxy-Propane TorchMany other old and cold goodies"Rusty but Trusty"
Reply:Originally Posted by lars66If you try to weld over the mess with dual shield you are going to make a bigger mess.
Reply:get a box of insto-weld.simple,all you do is open the box, add a cup of water,n shake it up, pour it in the weld...you're done, simple as that, anyone can weld now!lol.  shortcuts?face all times with a positive mental attitude,then and only then will you have done your best.
Reply:Originally Posted by iron mikeget a box of insto-weld.simple,all you do is open the box, add a cup of water,n shake it up, pour it in the weld...you're done, simple as that, anyone can weld now!lol.  shortcuts?
Reply:I do agree with everyone who is saying that I should grind out the bad section and just re-weld.Maybe the question will make more sense in context.  I am taking welding courses, and we just started on FCAW-G.  I have been doing really well with this process, so my teacher sent me into another student's booth to help him out.  His practice piece was very uneven, with lots of spatter, blobs, etc.  It was very strongly implied that I should be able to "fix" his welds simply by welding over them.  Also, today, I was doing some vertical up dual-shield welding, and I started out with improper technique, resulting in very porous welds, and again it was implied that I should be able to "fix" it (i.e. even it out and create a flat surface) by welding over it.In case it helps, I am running .035" Murematic wire at 19.2 volts and 275 IPM with 100% Argon at ~30 CFHAspiring Top-Notch WeldorLooking for work/experience in Eastern Massachussetts
Reply:Pics please.Bubble gumTooth pixDuct tapeBlack glueGBMF hammerScrew gun --bad battery (see above)
Reply:Originally Posted by akatzIn case it helps, I am running .035" Murematic wire at 19.2 volts and 275 IPM with 100% Argon at ~30 CFH
Reply:Why 100 % argon gas? maybe I am missing something, but I thought you are welding steel?Esab 253 mig welderHobart 210 mvp w/ C25 gasmiller 225 a/c stick welderO/A torchHF 40 amp plasma cutter
Reply:Originally Posted by BurpeePics please.
Reply:I would use 100% CO2. That is what we used to use in the structural ironwork up here, some wires may be ok for 75/25, but check the labels. Most of what I used was CO2 preferred... That might be mostly do to the cheapness of the plant foreman too... But good place to check none the less...TOOLS AND TOYSSMAW Mid States Inc. "MISSING LINK" 10-150 AMP Buzzer circa 1945ishSMAW Magic Wand 40-60 AMP Suitcase Buzzer circa 1939ishGMAW Hobart 210 IronmanOxy-Propane TorchMany other old and cold goodies"Rusty but Trusty"
Reply:I only use 75/25 gas or 100%Co2 gas for mig welding, with hard wire and dual shield. I use argon gas for tig and spool gun with aluminum. never heard of it being used with mig.Esab 253 mig welderHobart 210 mvp w/ C25 gasmiller 225 a/c stick welderO/A torchHF 40 amp plasma cutter
Reply:Sigh.FCAW-G wires come in lots of different 'flavors'.  Some use 100% CO2 as the shielding gas, some use C25 (or C20 or C10 or similar), some can use either (with slightly different runnning parameters and slightly different metallurgical properties after welding due to the different shielding gases used).RTFM and it will flat-out tell you what gas you should or can use with that particular wire.And I don't see any single mild-steel FCAW-G wire for use on mild steel in the ESAB or Lincoln catalogs that lists the use of pure argon as the shielding gas.  The use of pure argon as the shielding gas for FCAW-G is not even listed in the AWS A5.20  categories for mild steel.RTFM.As to welding over some existing crap, that almost always means that the previous 'crap' is still there in the weld or the bead or the joint.  Best practice is to ALWAYS remove anything from the joint area that is not clean metal (steel in this case).  No rust or corrosion, no paint, no grease, no oil, no water, no pigeon-poop remains of some sort of bubble-gum almost-weld of questionable parentage or metallurgical properties.Sometimes, with some welding processes (SMAW with certain rods mostly, sometimes various FCAW 'flavors', rarely GMAW and even less rarely GTAW) you can 'get away' with or 'tolerate' certain amounts of not-cleanness in the weld area.But you ALWAYS get a better weld if you have clean shiny metal to weld.  The best laid schemes ... Gang oft agley ...
Reply:Originally Posted by akatzIn case it helps, I am running .035" Murematic wire at 19.2 volts and 275 IPM with 100% Argon at ~30 CFH
Reply:Originally Posted by akatzI don't have any right now, unfortunately Can you explain which part of my setup is problematic please?Yes, I am welding steel.  Last class I was using 75/25 Ar/CO2 mix, and today I was on the machine with pure Ar.  My teacher said that we should practice welding with different shielding gases to get used to the differences.  I thought that 100% Argon is the preferred shielding gas? Personally, I have had the best results with the 75/25 mix.Thanks everyoneOriginally Posted by Steve French100% argon for FCAW doesn't really make any sense. You sure you aren't running 100% CO2?Check this thread out: http://weldingweb.com/vbb/showthread.php...-TIG-explainedI don't think you have said exactly what you are welding (thinkness, type of joint, etc) so just guessing you are maybe running stringers on some 3/8" plate or similar?Switch to straight CO2 (or 75/25 at least), 20-25 CFH, and try 23V and around 230wfs to start. Pictures of your welds would help too.
Reply:Whew. Either your instructors are grossly incompetent or you are misunderstanding their instructions. If this person is seriously suggesting 100% Argon for MIG on steel you should be taking lessons elsewhere. OTOH, if you are confusing solid wire and dual-shield, perhaps you are not understanding what he or she is saying. Either way, something is seriously wrong with this picture and your last post shows that you are aware of this.The major manufacturers (Miller, Lincoln, and ESAB) have lots of great info on their sites which is really worth your time to look at.JohnA few weldersA lot of hammersA whole lot of C-clamps