Continue from:
Soldering silver to Aluminum
https://orchid.ganoksin.com/t/soldering-silver-to-aluminum
and
Welding gold to steel?
https://orchid.ganoksin.com/t/welding-gold-to-steel
After some thought and talking to my brother who is a Non
Destructive Material Testing engineer, Aluminum and silver, try
epoxy, the only thing you can bind to aluminum is aluminum, that is
generally a welding process.
Gold to steel, a layer of copper or nickle is needed between the two
so that silver solder will have the maximum hold. I have a Lincoln
Precision Tig 275 welder in my shop, it’s a big honker of a unit,
but I can fuse copper to copper with no flux and gold to about any
ferrous metal. I can get two needles to weld tip to tip without
burning the metal or weld boiler plate to an armoured car. But this
is an expensive machine and worth, every penny, great for small
work.
Jerry