downhill gmaw

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was building a water stand today for a large bridge project were doing. this monstrosity is shaped like a octagon made from 6" i-beams. it will hold a 20,000 gal. water tank so they can gravity feed the water to the system. well i lay out and start fabbing this bad boy up. i make my first few welds and think to myself "oh yeah, this is gravy" every part was pre-cut by an outside firm, the angles were perfect when i fitted the first 3 pieces. in the notes section of my print, the engineer (or whoever drew them) stated downhill gmaw. well being born a stick welder, vert up all the way. but my shop shies away from smaw. these fellas love them some mig. well i ran vert up on the web spans of the i-beam. big boss man comes by and sees the torch travelling up and stops me to let me know the print calls for downhill. i'm stumped, i have heard of pipeliners welding down, but structural. i have never done it. i practiced on some scrap and welds look good, but i am worried about strength and liability of my welding killing someone. any help would be appreciated."Retreat hell, were just fighting in the other direction"Miller Trailblazer 302, Extreme 12 VS, Dimension 400, Spectrum 375, HF 251D-1, Milermatic 251 w/ spoolgun  Hypertherm 1000Lincoln sp 1702000 F-450 to haul it
Reply:You can run vert down short circuit.... I use it a lot depending the application. Mostly on thinner materials.... or maybe a cover. The trick is to keep the arc under, or ahead of the puddle._________________Chris
Reply:i am running mm251. don't know if it short circuit or what?"Retreat hell, were just fighting in the other direction"Miller Trailblazer 302, Extreme 12 VS, Dimension 400, Spectrum 375, HF 251D-1, Milermatic 251 w/ spoolgun  Hypertherm 1000Lincoln sp 1702000 F-450 to haul it
Reply:That is a short circuit welder.
Reply:i practiced on some scrap and welds look good, but i am worried about strength and liability of my welding killing someone. any help would be appreciated.
Reply:Maybe one pass up, then one down for looks?" One final pass for cosmetics "  An expression of my dads.That is a tough situation, I only weld exhaust on a car verticle down.  Every thing else is UP.  Its much stronger, we all know that.Welding instructor told me 26 years ago, Verticle down is a wash.  I still agree.You do not have any liability in the job.  This is why I am self employed.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:you can run GMAW down and get a good weld if you know howand i got the cert's to prove it ,but you need to keep a close eye no it to make sure you don't let the puddle get a head of the arcChuckASME Pressure Vessel welder
Reply:If you combine what chopper and sandy say, this is what you'll have:Provided you make a acceptable weld meeting the criteria of the specifications of the engineer you should not be held liable, So the liability falls on the engineer! And if you deviate from the criteria, then you assume liabilty because you are not following the engineers criteria, just my two cents.
Reply:I agree with Sandy.  You have to do as the print says.  I can only guess that the engineer wants a sealing weld only????  I have this kind of thing happen all the time where we are asked to little welds where you would expect more and other times so much weld that the unit distorts.