I *think*, from memory, that the aluminium brazing rods I had were a high zinc content alloy. Can't remember the exact mix. Did some tests, worked OK on a properly cleaned joint with a lot of surface area (think "sweated" pipe fitting type joins), but were bloody awful, no matter how good the prep work, on anything that took a peel or pull off load. "Stronger than steel" my cock.
For glueing, I wouldn't worry too much about "keying", it's more about removing the natural oxidisation beforehand. I believe most of the heavy duty aluminium bonding solutions (aerospace, etc) use some sort of super-exotic cyanoacrylate and some super-gnarly surface treatments, but you'd need micron tolerance and a lot of money for those, I'd think. A "structural" epoxy should do the trick. I've got away with the "wetting with epoxy" approach, otherwise surface prep is pretty much "stainless brush, acetone or MEK surface wash, rough, rewash, clean air dry, glue"
Hell, if your surfaces are flat you might even get away with some of 3M's tapes. They're outstanding. I did a 9m prototype power kite with almost only tape bonding once (obviously, this was on polyester rather than aluminium, brand name "icarex", it's pretty hard stuff to bond). Only sewed the bridle attachment points, taped the rest. Lasted 2 years of buggy racing on beaches - salt water, sand and sudden shocks - before it started to peel in one corner after being stowed wet by a "friend".