I checked it out also. Unless there is a portion I'm missing here is what they say about finishing:

This is a critical aspect of pipe making that is often the demise of an otherwise nice pipe. Finishing a pipe can take often take as long, or longer, than the shaping of the pipe. Care in this process is worth it, as the result will be both beautiful and lasting.
Edit - Yep that was fast. I was missing a lot. There are all sorts of links on the topic.