While there are still some shapes you can't make this way, if you extend your manufacturing techniques to involve resin casting you can easily mass-produce comp

While there are still some shapes you can't make this way, if you extend your manufacturing techniques to involve resin casting you can easily mass-produce complex shapes. That's the motivation fo the Guerilla guide to CNC machining (which is an excellent link, btw): http://lcamtuf.coredump.cx/gcnc/ http://lcamtuf.coredump.cx/gcnc/ Even with a 3D printer that's how parts are going to be mass-produced. Yes, 3D printers are awesome for prototyping and small batches, but if you get into any volume casting will be a lot easier. Scaling up in size, you can sand cast aluminum at home relatively easily, and even do iron if you can build a big enough furnace. That makes it possible to build an engine at home, entirely from scratch (ok - starting with scrap aluminum and some cold rolled steel), bootstrapping what you need. The gingery books explain it all: http://gingerybooks.com/ http://gingerybooks.com/