MIG Welding vertical surfaces

Hi,
On the weekend I was welding 3mm angle iron together.. I got some great looking welds when I was welding on a horizontal surface, but it
all turned pear shape when I tried welding the same two surface that were presented vertically.. Where do I start? Top? bottom? do I use a continuous bead? Do I pause and let the puddle solidify every .5cm or something? I'm sure there's a technique I need to know! :-)
Any help much appreciated..
Tks, Duncan.
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vertical gmaw should use short circuiting or pulsed spray method. if youre running smaller wire you can also use spray transfer. it sounds like you were running vertical up and you were either set to high or you werent running fast enough. you can weld vertical up or down with GMAW with equal results. vertical down is typically easier depending upon your level of experience. in the meantime, if you use the short circuiting method your pool will run the coolest allowing you to run a little slower.
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Your metal is too thin for vertical up. Run it hot vertical down with pretty small wire, and slight weave.
Vertical up is for metal starting at twice your thickness.
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Vertical welding with GMAW is always a tricky thing. You are adding a lot of metal. So, it is difficult.
I, personally have not had a great amount of luck welding GMAW vertical travel up. Since most of the things I MIG are thinner stuff, I just weld everything down. Usually things that are structural and need good penetration are of much thicker materials than 3mm. For the rest, I use downhill. With downhill, you can turn it up and run faster. You can weave. You can make multiple passes, but just don't make several cold downhill passes, or you will not have a lot of strength.
Don't know if this is the right way to weld things, but it works for me. If I have anything that really needs to hold, I crank it up, or if it is thick enough, use 7018. Sometimes you can even reposition the piece.
Steve
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Guys,
Thanks for the advice, I'll try some of it out on the weekend.. I'm not really sure what my welder is capable of.. its a BOC 250C.. perhaps its rebadged from something you guys might know..
You can see a photo of it here (and I have no idea what half of this stuff means :-) )
http://tinyurl.com/wjlx
The specs I got from the BOC site are:
Supply voltage (V)    220 - 240 Frequency (Hz)    50/60 Phase    1 Rated primary current (A)    25 Supply fuse (recommended A)    32 Supplied primary plug (A)    15-Limited Output Primary cable length (m)    3 Welding current (Amps)    30 - 250 Duty cycle    30% @ 250A Output voltage    17 - 41.4 Voltage steps    16 Inductance settings    2 Polarity change for gasless wire    Yes Remote interconnection cable lentght (m)    n/a BOC gun/length (m)    MG25i/4 Number of drive rolls    2      Wire feed speed (m/min)    0-18 Wire diameter (mm) Solid    0.6 - 1.0 Soft    0.8 - 1.0 Flux cored    0.8 - 1.2 Wire inch & auto wire load    Yes Stitch/spot weld    Yes 2T/4T switching    Yes Burn back control    Yes Isolated electronics    Yes Fan on demand    Yes Copper transformer    Yes
I'll let you know how I go on the weekend..
Cheers,
Duncan. Adelaide, South Australia.
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