Franken, I use Nozzle spray...I dont like the dip because it drips out of the end of the nozzle when you pull it out of the "tub" it comes in. I use a spray. I spray the material and the nozzle on the gun. As you mentioned, welding on old, dissimilar metals is probably your biggest problem. There is so much crap imbedded in old material, even though it looks clean, it is still usually contaminated to some degree.