When I belonged to the Chabot Observatory, they had classes for it, and mirror-grinding. It was pretty straightforward- just required a lot of elbow grease. They had all of the necessary instruments for checking your work as you went along, and lots of helpful people to get you on the right track. Great bunch of people.
Several years ago I took a piece of glass with me on a business trip to San Diego and worked on it in their workshop. I got to look at Saturn through the scope (20" Clark refractor). Then I went to a star party on Mt. Hamilton and saw it through a 7" Astro-Physics refractor.