welding tricks

[IvelDesigns]

so i'm not sure how to put this without sounding like a complete welding noob, but here goes.

I have a Clarke 110v welder. It has treated me well so far, other than popping the fuse for my garage when i get it cranked up to 3 or 4 (I need to get a 20amp breaker instead of the 10amp it's on).

But anyways, when i weld new steel, it does great. Even on stuff thicker than i should be welding (.25 mild steel), i get great penetration. But the other day i tried to weld a temporary crossmember to my frame and i could not get penetration into the frame to save my life. So much, or little i should say, that the weld didn't stick to the frame at all. But it penetrated the new steel i was using just fine (.125 mild steel). It was also popping my breaker every 15 seconds or so. much more often than normal.

so my question is, what can i do to get the best penetration into my frame? I ground off all paint/rust/dirt, made sure the ground was on a good surface, etc.