I've been working on tubeing lately and I can't seem to get penetration unless I bevel the edges or blast it with heat and burn up the material. My instructor told me that the tubeing is thin enough to where i shouldn't need to bevel it but I don't know how to weld it without makeing it black and ugly.

Second when I bevel it I can't seem to get the weld to cover the entire area to make it look flush, once again too much heat and it burns up on me. I know how to control heat but it just seems that I can only weld small beads for some reason. The tungsten size escapes me right now and I'll post some pics.

 

Try putting a gap between the pieces as big as your filler rod for practice. I do this by bending a rod into a V shape, and putting it between the tubes before I tack weld. Like this (V). You'll get the penetration, but if you don't go quick enough or are too hot you'll probably blow holes. Good luck.