Glass artisan Charles Flickinger with molds for bending glass, Flickinger Glass Works
The structure to teach artisans has changed over the last two centuries in America, but many artisans still learn their skills from master craftsmen. When glass artisan Charles Flickinger set up his workshop in Red Hook, Brooklyn in the 1980s, the glass works he purchased included hundreds of custom made metal molds for bending glass which dated back to the 1830s.
See this photo in the exhibit Landscape of Lost Arts.