Are there consumer-grade 3D printers that can print copper?
Or print a hobby-sized version of a rocket (out of some heat-resistant material)?
(I'm thinking about the model rockets you may have had as a kid with an A8-3 engine.)
That said, 3D printing an easily-removable mold for coring, such as from wax, would be amazing.
If the failure cases are dangerous (magnesium fire?), then the safety precautions might keep it out of general consumer availability.
This is selective electroplating by only applying electric current to pixel sized areas and building up the object layer by layer like a resin printer. It's truly amazing what it can do. It's just really new.