Ceramic Tape Welding Gone Wrong

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We will let the photos speak for themsevles.I have never dealt with ceramic tape welds before.  One side came out perfect one side failed miserably.  Perfect side was root passed same day tape was installed other side was rooted one day later.  Our speculation is that the tape absorbed moisture overnight and the water steamed out during the welding process to cause porosity.  It is the only thing we can come up with that doesn't involve shielding gas coverage problems.  We're just trying to stick the shipyard for the bill for the rework because this is clearly unacceptable.  Process is .052 ESAB dual shield wire with CO2 shield on ceramic tape, 3/8" thick plate.
Reply:I would say by looking at that its most definitely gotta be the backing strip or gas coverage problems.     While i have never encountered that particular problem it sounds very plausible. The ceramic backing bars i have dealt with have all be very porous type of ceramic that would seem to be susceptible to absorbing moisture.Vantage 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:Why continue to run and finish a long length porous weld, when it becomes obvious that something's not right?Blackbird
Reply:why are you using CO2 and not 75/25?  is that beveled on the overhead side?Last edited by TimmyTIG; 01-29-2013 at 05:50 AM.
Reply:It would seem that the person welding would have payed attention to how it was welding and stopped rather than continuing the complete weld.   As far as trying to make the ship yard pay to repair for a welders mistake - that seems like they way of a lot of todays people are  -  Do something wrong then blame someone else and try to make them pay.  Seems like the shipyard needs  to be looking for some qualified welders to do their work for them.
Reply:agreed on the welder not paying attention.    As far as the strait C02 vs 75/25  the c02 is far cheaper and offers superior dig characteristics on dual shield welding applicationsVantage 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:Originally Posted by dave powelsonWhy continue to run and finish a long length porous weld, when it becomes obvious that something's not right?
Reply:note:  Some FCAW-G wires are made to run with 100% CO2 ,some are made to run with argon-CO2 blends, and some can run with either.  RTFM!!!example:  AWS E71T-1C wire runs with CO2 only.AWS E71T-1M runs with mixed gas (C25 or higher argon mixes) only.A wire classed as E71T-1C, E71T-1M, E71T-9C, E71T-9M meets the specs for multiple AWS classes and can run either 100% CO2 (the C in the spec call out) or mixed gas (the M in the spec call out) like C25.But you probably already knew all that.  ESAB currently lists 15 different DualShield FCAW-G wires for use on/with mild steel (AWS A5.20 spec).    Some use 100% CO2, some use C25 or similar, some can use either straight CO2 or mixed gas.  Some can use straight CO2 if doing a single-pass weld, but call for Ar/CO2 blends if doing multi-pass welds.As to the porosity,  yeah it's pretty bad.  Complete grind out and redo there.Maybe a quick call to ESAB for some tech help, maybe they have some possible insight beyond (yeah, grind out and redo).  1-800-ESAB123or Do you have a question about welding or cutting that you can't find the answer to?  Let ESAB's experts help.  We have welding application experts standing by to help you find the solution to your problem. Filler Metal Technical Support800-934-93538:30AM - 5:00PM EST
Reply:I take it most of you have never worked in a shipyard before... I have seen way worse come from "qualified ABS weldors" haha this is nothing compared to some of the stuff I've seen...
Reply:This wouldn't be a shipyard in Canada, at the lake Ont end of the Welland Canal. The vessel wouldn't be Canadian Coast Guard would it?
Reply:This is a ship assist tug in the San Francisco bay area.
Reply:Originally Posted by sftyvlvThis wouldn't be a shipyard in Canada, at the lake Ont end of the Welland Canal. The vessel wouldn't be Canadian Coast Guard would it?
Reply:Thanks Stump, worked at PWDD a few years ago and had this problem. Put the ceramics on one shift next shift went to weld  instant "aero bar". We used Co2 and Lincoln 71T series wire. Can't remember the parameters, but I think it came down to moisture causing the problem.