Tacking with smaw.

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I used to work in a shop 2 years ago with everything was tacked with SMAW with 7014 X 1/8 welding rods, we used to make small structural parts and stairs, then it was welded by the welder using MIG with i don't know the technical name of the solid wire that they use!After i worked in another bigger shop where all the fitters was using metal-core wire and it was welded by flux core wire!and now i work in a bigger shop than the others with a lot of standards and rules, this place all the structural is tack welded with SMAW using 7018 X 1/8 rods that one structural inspector told me this 7018 rods is a special one its only use to tack weld!at this place almost everything is welded by flux core! for sure im doing what the shop standard want and require and i won't do my way i only ask here for some extra infos, but my question is there a specific reason OR a technical reason about what rods or wire using for tack welds ? is it about cost or something like that ? what is the difference about tacking with 7018 rods and 7014 rods ? what about this 7018 rods only made for tack welds ? im losti also have to say that i live in canada, to avoid welding nazis saying ''we can't answer because of standards of different country''Last edited by LayoutMan; 07-13-2012 at 05:03 PM.Calculator > Bevel Square
Reply:Hi I prefer 7014 myself if the inspector  isnt looking , thr problem is it is not low hydrogen and some structural specs require it . E-7018 is not special tack rod for any brand . We only have 8018 C3 in the bridge shop as we deal with A-588 all the time . We do FCM D1.5 / D1.8 work which is all low hydrogen and subject to heavy inspection . For the basic structural and misc. work where Spec is E-70xx ise E 7014 , E7024 E7018  . For low hydrogen E-70xx Use E7018 E-7028 .  Old school use 7/32 or 1/4 E-7024 E6027 E6012 and E-7028 on AC ,  it will eat up .045 Mig or FCAW .
Reply:When I worked at a heavy duty fab shop as their sawyer, all they did to tack was hard wire mig.  All of the structural welding on the steel end of things was done with dual shield.  The place did lots of tooling for Boeing, fuselage carts, wing join tools, etc.-AaronJet 17.5" Drill Press1942 South Bend 16x84 Lathe1980s Miller 320A / BP --- 2013 Power Mig 2562012 Jet 7x12 Horizontal BandsawVictor O/A Setup
Reply:Under CSA you have to use a low hydrogen process so the choice is E 7018.  If you are using SMAW you have to use E 7018, E 7016 (not common) or E 7028.   In some cases you would use a higher strength version.   E 7014 is not a low hydrogen electrode.   I have never heard of a "tacking electrode" however some manufacturers boast that their electrode re-strikes more easily.