[Greg Reid]

All that looks very, very familiar. Very fine job of welding and that's the kind of information I'm looking for on the rust removal.
Looking for something a little stronger than Evaporust or Naval Jelly. I hear that Muriatic acid is very aggressive but can be destructive if not neutralized quickly.
I've made good use of twisted wire cups and wheels on an angle grinder to prep for the de-rust treatments. I'm familiar with the bristle discs and I like them but the ones I've had were only 2" and wore out quickly. Pretty pricey is right. Excellent for removing paint. I used them on a pneumatic rotary tool and my compressor has a hard time keeping up.
Have you tried vinegar? There are some interesting claims about it's rust removal qualities and it's only a dollar or two a quart. I plan to try some.