Thanks for the picture, it helps a lot!
That is small enough to fit into an EDM machine, and can be submerged in the medium.
Be careful with heat. You could change the structural character of the hinge material or worse, melt it.
Zinc melts at 780ºF, Aluminum 1220ºF. A propane
torch flame is about 3200ºF' acetylene/oxygen is 6300ºF!
Maybe your Dad knows someone who does EDM.
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Whether you think you can or think you can't, you're right.