mig penetration

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i bought a hh 187 and really like it, im using c-25, .030 wire. is the penetration adequate? upright is 3/16 base is 1/4..also i noticed it seems that a straight stringer bead has better penetration than a weave. It this correct? also is vertical down with a mig ok? thanks tonypict 7738 left side is vert. down, right side is slight weave flat, im puzzled by the lack of penetration on the flat weave bead... Attached ImagesLast edited by tony j; 05-05-2007 at 05:23 PM.
Reply:They look pretty good to me.  Its not so much penatration, its fusion.  Weld has to bond to plate.  The welds look good to me.  I find if you " weld the two pieces together" instead of welding the joint like with stick, you get a better weld with MIG.ONLY MY opinion.Heat, travel speed, gun angle.  All effect weld.   Did I mention HEAT?DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Yup, I think penetration is a pretty abstract term used in welding...if you get complete fusion and weld is the correct size, that´s the way to go (based on mechanics of material class)your welds looks 100% fused to meMy Babies: HF Drill pressHF Pipe Bender3   4.5" Black and Decker angle grindersLincoln Electric PROMIG 175that´s it!
Reply:I don't agree about penetration not being important.  If there is no penetration, it is possible that the plates themselves are not fused together, you just have weld fused to both plates, which, if you bend the joint from the other side, you could possibly break it.  However, most of the welds do appear to have decent penetration.  In anycase, full penetration will always be stronger than not because there will be no void in the material at all.  But, this stems from being a pressure vessel pipe welder, so you might not need full pen. to work well for you.
Reply:If you want better penetrations try straight C02. It works for me.Miller Millermatic 252Miller Syncrowave 200Liincoln AC-DC 225Victor O-A Set
Reply:on 7739 right hand fillet you have lack of fusion on the vertical face.On 7740 you have lack of fusion at the root, left hand side.  Generally the arc has to melt the corner as you go.  Incorrect angle or incorrect motion can contribute to these problems.    The largest problem is with 7739 because one side of your fillet weld is faulty.  The metal is there but the plate is not fused to the weld bead.  The condition is often called cold lap and it typical with MIG welding done carelessly.  Generally your weld bead profiles look correct.
Reply:thanks for the replies, i think the gun angle is my problem, also the further i weld the gun goes to a push angle, i have about 20 minutes total mig time, i have alot more tig time....thanks.....tonyalso is vertical down ok?
Reply:Your 7738 vertical down is nice and small.  If you try to make large beads vertical down you will find the puddle overruns your arc and you get lumps and cold lap.  Keeping at the leading edge of the puddle is what you did and it was correct.  On the right hand side you can see that the vertical leg has fused deeper than the horizontal leg.  That horizontal piece has more paths for the heat to travel so it is a larger heat sink.  I am sure you have experienced a similar problem with TIG.  large weaves are risky with any process if you do not ensure that everything is fusing properly and you are not creating cold lap.    Cold lap is a common problem with wire feed welding.  The bead looks fine but the toe of the fillet just does not look right.  I have had the bad experience of it showing up as a line when the finished article was painted,   OUCH!