MIG Questions

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Hi WedlingWeb,    I have a question about MIG welding today.  How can I control the height of a bead?  I know that in SMAW welding, the bead height is related to the heat as determined by the current.  Hotter welds wash out and lay flat.  That, and a slight weave also seems to help flatten things out (maybe this is a result of greater heat input?).    In any case, I know that on a MIG machine, I can adjust the current by increasing or decreasing the WFS.  This is where I get a bit confused:  If I were to increase the heat (current) by increasing WFS, would I still end up with a high bead because more material is being fed into the weld as opposed to a lower WFS?  And if I increase my travel speed so that less material is deposited per unit length of weld, would I have an issue with inadequate heat input and therefore a high bead/cold weld?  Finally, how does voltage adjustment play into all of this?  From what I understand, voltage basically determines the arc length.All help is very much appreciated!Aspiring Top-Notch WeldorLooking for work/experience in Eastern Massachussetts
Reply:Bead height is controlled by a number of things with mig.Pushing the bead will give you a flatter bead than dragging, all other settings staying the same. Decreasing your stick out will increase the heat and tend to flatten out a bead while increasing stick out will cool the bead and give you a taller bead. Wire speed and voltage are interconnected. Some times going up in volts while maintaining the same wire speed will  flatten a bead, also deceasing the wire speed at the same voltage give you similar results. Dropping down in wire size may allow you to run faster wire speeds, yet not put down as much filler causing a flatter bead. Puddle manipulation will also help spread the puddle and flatten a bead..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:How would increasing or decreasing stickout change the heat?  I am confused because regardless of the stickout, the voltage and amperage settings would remain the same (I think?) and therefore the arc length and heat should be the same (I think) regardless of stickout.EDIT: Not saying I don't believe that stickout has an effect on the heat, just trying to understand the why/howBTW, this relates to a vertical up weld made with .035" Murematic wire, WFS 275 (dropped it down to 265 at the end), 19.2 volts, 75/25 Ar/CO2 mix @ ~40 (roughly) CFHBased on the list of factors that you wrote, I might guess that my WFS needed to be a lot slower...Last edited by akatz; 03-17-2014 at 01:24 PM.Reason: clarificationAspiring Top-Notch WeldorLooking for work/experience in Eastern Massachussetts
Reply:Originally Posted by akatzHow would increasing or decreasing stickout change the heat?