Charles Mak writes:
"I was looking for soldering info, since soldering, I believe, is a technique an automaton-maker should be familiar with. In fact, some works by Neil Hardy require soldering for their mechanical parts. I came across this site which offers more than just soldering technique but also a wealth of (free) information on materials, preparations, sources, etc. It's all free to view and print, but for those who prefer a 16-page color book, they can order it or download it for a fee."
Most online tutorials assume you want to solder electronics. While the principles are the same, the process is a bit different. Here is the site with free soldering and metal-working tips. (You'll need to scroll down a bit to find the start of the article.)
For a comprehensive reference to metal-joining techniques, you might take a look at Soldering, Brazing and Welding, which looks to be a great book on the subject.