Welding structural A304 stainless steel?

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Hi everyone,I have a job for some wheel chocks and seismic bracings for an MRI trailer at a hospital.  I am needing to weld 1/2" A304 plate together to form an angle.  The welds are to be CJP.  There is approx. 14 feet of plate to weld together! I need some help as to how to weld this.  Through the little research I did, I found out I need to use 308L as the filler metal.  I found some FC wire (self-shielded) available in .035, .045, and 1/16"I would like to use our LN-25 mated to our EX300.  My main questions are:  has anyone welded stainless with 308L FC wire?  How does it run?  We usually run .068 wire and up in our LN-25s, what do we need to change to run 1/16" wire, tip? Roller?  I'm guessing 1/16" wire will work fine because its so close in size to .068?Thanks for any insights you may have.
Reply:Ideally, 347 rod and TIG is your best bet. If you had a giant tungsten and big machine you could probably do that in one pass and not use rod. Short of that, I would stick it. Thin 3/32" rods, a lot of amps. It will shine and stay bright between passes and the flux will roll off by itself.        Sincerely,             William McCormick
Reply:Hello gfourth, you've got a doosy on your hands there. That is not to say that it can't be done, yet since we are speaking of stainless and long lengths with a fairly substantial amount of weld required you are possibly going to have a spaghetti nightmare(warpage). You can do this with the flux-cored stainless wire(preferrably dualshield wire), yet it will require a lot of prep-time, back-step welding, back-grinding, and stout fixturing or a mechanical straightening process after the welding has been completed. I will be interested to hear others suggestions for you on this one. Did I mis-understand the length, is that total weld or is that the actual length of the pieces? Best regards, Allanaevald
Reply:isn't 1/16 wire a little overkill for 1/2 material??
Reply:Grab some dual shield wire and do it that way.  We recently purchased a 30lb roll of .045 dual shield 309L for cladding 304 plate on mild steel.  It was $300.  This was all pushed through an LN-25.  The liners should be compatible, mayby just tip and rollers will need to be changed.  We use the .045 wire for everything ranging from 1/4 inch to 1.5 inchs.  .063 does seem a little overkill.
Reply:I'm a bit old school my father wasn't really an "early adopter"  I would just weld it up with AVESTA 308 3/32" in a couple of passes.   back step and clamp the living snot out of it try and minimize distortion.   if they did end up getting some warp in them i would look into thermal striating them.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:Originally Posted by aevaldHello gfourth, you've got a doosy on your hands there. That is not to say that it can't be done, yet since we are speaking of stainless and long lengths with a fairly substantial amount of weld required you are possibly going to have a spaghetti nightmare(warpage). You can do this with the flux-cored stainless wire(preferrably dualshield wire), yet it will require a lot of prep-time, back-step welding, back-grinding, and stout fixturing or a mechanical straightening process after the welding has been completed. I will be interested to hear others suggestions for you on this one. Did I mis-understand the length, is that total weld or is that the actual length of the pieces? Best regards, Allan
Reply:Hello again gfourth, do you have any other feeders than the LN-25s? As some of the others have suggested the .045 dualshield SS wires would probably work very nicely. I have had very little experience with the SS self-shielded wires, yet, the ones that I have been around are not nearly as user friendly and sanitary as the dualshield ones. You may wish to consider getting with your local welding supplier and see if he would be willing to bring you some wire to "test drive", in this way you might be able to see the real differences between what is out there to use for this project. The dualshield wires are "very" smooth and require little clean-up, most of the self-shielded ones are much more labor intensive with regard to finish cleaning. In many cases the self-shielded wires are much more expensive than the dualshield ones and even though you have the addition of gas for the dualshield ones they still are more economical to run when comparing the cost of the consumable and the clean-up times and additional labor. Just a bit more for you to consider. Best regards, Allanaevald
Reply:gforth is it really necessary to have a CJP? The 308 flux core will work fine and if you do not need CJP the stitch weld it to prevent distortion then try back stepping and clamping. You are correct in the bigger liner should handle the 1/16" wire and change the rollers and tips. Look into a smooth and a V-knurled roller.Weldor/ Certified Inspector
Reply:I've only used dualshield for stainless but we used to mix self-shield and dual shield for mild steel.  I've ground out too many porous welds with the self-shield and even seen some fail before a load was even applied.  Dual shield is the way to go.  It's also much more user friendly.  The flux just falls off.  The spray transfer allows for trigger welding when you get to a spot that likes to burn thorugh.  Once you go dual shield you'll never go back.  All of your machines will get converted.
Reply:If you were mixing the two wires that's the reason you were getting porosity. YOU ABSLOTELY CAN NOT mix the alloying agents of the two different wire types.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:This  contract be beyond my experience and training , but Im interested in some others thoughts on the following?In reference to Strength Vs Time Vs Economics Vs Dimensional trueness and Straightness Two ideas:A) welding two  4" flat bars to a 4x4 angle... (twice as much welding)B) folding a sheet ....(big bloody folder!)A good guess is better than a bad measurement