cool man, happy you got it figured out

Only use a stainless steel wire brush for cleaning alum.If you used the SS brush on mild steel get a new one.Dont use a flap wheel from steel then to alum.If you are sharpening you tung. horz. to the grind stone this is wrong.Get a tung. sharpener.Makes the points last longer.Try using a gas defuser len's also.Provide's better gas coverage.I use denaturted alcohol for cleaning alum parts before welding.

Is that strong enough? I use acetone. But if something else does the same job for cheaper than I am all for it.

If the parts are real dirty I bead blast first then wipe clean w/DA.