As the title says I'd like to know how saltpeter was manifactured during the golden age of piracy. Although I am intrested in knowing where it was manifactured (any dominant exporters), the process of making it, and what saltpeter was valued at. Sorry if I bombarded the question with questions but google wasn't really my friend when it came to this topic.
Shit!
OK, that's a simplistic answer, but let me explain. During the golden age of piracy (I'm going to be generous and just say 1600 to 1700), the vast, vast majority of gunpowder in the Caribbean came from Europe. At this time, Europe (and especially England) was getting its saltpeter from the Continent. This was a big problem whenever England got into one of its regular wars, disrupting this supply.
To get around this disruption, there was a whole network of saltpetermen who organized a governmental program of fecal collection and use [WARNING: Will download a .DOC file.]. They built and operated saltpeter beds, filling them with products collected from an unwilling populace. The saltpeter program was immensely unpopular because it was so onerous. Imagine having to let strangers into your stables, cellar and outhouse to dig it up. Furthermore, the saltpetermen were notoriously corrupt, and the whole process was a nasty business. Even after all this, the stuff they came up with was of poor quality, since it was lime saltpeter.
Jamaica was captured by the English in 1655 and believed to have good saltpeter deposits. Antigua, too, was thought to have these, and a mill was built there. Attempts to make gunpowder on Antigua abruptly ended when the works blew up, killing the sponsor. The Caribbean didn't amount to much saltpeter production during the period in question.
By the end of the 17th century, however, England and the rest of Europe found its solution: India.
Indian saltpeter was the best in the world, by virtue of manufacturing techniques honed over hundreds of years and a climate that was much more favorable for saltpeter production. The shipments of saltpeter began in the last years of the 1620s and really took off by the end of the century as British influence spread into Bengal, source of the best and most plentiful saltpeter.
If you want to learn more, check out David Cressy's book, Saltpeter: The Mother of Gunpowder. It's extremely England-focused, but it gives you enough glimpses into the Caribbean and the rest of Europe to give you what you want.