Use a stainless wire brush and brush in one direction only! Do not use
a rotary brush it just scrubs the contaniments in deeper. Be absolutely
certain that the brush has not touched steel before or it won't work.
If you grind it make sure the grinder wasn't used on steel. Brush just
before you weld. Gas flow should be around 30cfh. PREHEAT. If you put
the filler in befor the base metal is hot enough it makes those cool
little black balls. Make sure you know what alloys you are trying to
weld. Some are difficult at best. The easiest to weld are the 3000
series.