We have looked at everything we can find. The aws welding journal, hobart institute, every magazine, and I've been searching online for a while. Still nothing. I doknow magnesium is not a very popular metal, so not a lot of people weld it. It seems to me like its contaminated, but from what. I have cleaned it with scotch-brite discs first, then MEK, and still the same results. If you've ever welded mag, or titanium, then you know that cleanliness is the most important thing. I've cleaned it every way I know how. There are other important things like, short arc length, leaving the filler in the puddle, but ??????..... I still don't know. I have tried changing the frequency, penetration, even the dcen, still nothing. The dcen is set at 105, and the dcep at about 98. This has produced the best weld. The freq is at 200 and penetration at 65, again the best bead so far. Do ineed more cleaning? It shows that I have enough. How about penetration? Maybe freq? I have also welded uphill as well as flat and horizontal.