MIG Welding Verticle

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I am going to be welding some 2X3 .083 mild steel square tubing in a T shape.  Two sides of this weld will have to be done vertical. I need to know what is the best way/correct way to do the vertical weld with the MIG processes?Some people say you can go either up or down, from what I understand going down will have less penetration.If I go up what is the proper technique?  Do I push or drag?Thank in advance!Mike
Reply:vert. down is easier for me to control and I use a Z or eve U weave to engage both sides. YMMV
Reply:How much would you need to penetrate 083 in a fillet joint? Its not an issue, run it downhand.www.urkafarms.com
Reply:malich,  Vertical down is much easier to control the puddle. Just try to go fast enough to stay ahead of the puddle.Bruce
Reply:ok, but we are talking about a rear subframe in a drag car.  Now am I going to have a lack of penetration and risk tearing out the rear subframe?The car is going to run in the low 8's.  1100+ HP.
Reply:Originally Posted by malichok, but we are talking about a rear subframe in a drag car.  Now am I going to have a lack of penetration and risk tearing out the rear subframe?The car is going to run in the low 8's.  1100+ HP.
Reply:i'd vert  up with fcawor use 7018 stick 1/8 in.and then 5/32 over that
Reply:use fcaw or 7018 stick  1/8 " first pass and then 5/32 for the second
Reply:Well whether you GMAW, FCAW or SMAW up or down here's what works for me. Verticle up==push using a very subtle up angle of the electrode. Maybe 5 to 10 degrees----not much. The tendancy is to really rake it back and that is too much. Use a slight side to side motion, maybe a full weave depending on the size of your filler. The point is to allow for a faster freeze by directing the arc away from the weldment but at the same time maintaining a good fusion. No bird poop welds.Verticle down==drag but again almost non existant angle, 5 to 10 degrees. Same motion, stay ahead of the puddle. Don't point the arc into the puddle, keep it on the base metal. The idea here is to obtain a slower freeze than verticle up which will allow overall better weldment blending and weldment fusion but there  will be less penetration. As Sberry said, on a .083 'T' joint amount of penetration is only one factor. Good fusion with the parent metal to filler material is another. Remember in a 'T' you are going to be filling in the entire corner. It's not like you are going to be grinding it flush. Also remember that no matter whether you use Gas, Flux or Stick, it ain't gonna hold up if don't do a good job.  Get some practice in.
Reply:Malich    There's a lot of good advice posted above, but you need to take a look at something before you do your welding if you haven't already. If you are building a race car that you plan to run in the 8's. Check your rule book. The only legal weld anywhere on the chasis is TIG. NO EXEPTIONS. Just a friendly heads up. Y'all have a great day.
Reply:Dr. C., you might be referring to a CM chassis as for the TIG welding.  I just spoke with a NHRA tech and he stated you can run 7.50 or slower on mild steel and it can be MIG welded.  He also said if the welds looked good with the FCAW method he would also accept that.Believe it or not, I actually saw a guy that stick welded his roll cage in and it looked like garbage and he passed tech.