Ran down to Paul b Zimmermanns after work with my boy. Decided to go stainless steel from the furnace to the new chimney. It's single walled 304, and man is it way thick! Much thicker then black pipe. I had a heck of a time drilling it to put the holding screws in. Hopefully it last longer then 2 years like the black pipe. Cost $168.00 for the pipe, 90* and 15* elbow. Only needed 14 1/2" of the straight section. But it's done.
While I was there I picked up a polly brush for cleaning the chimney. The directions were very specific not to use a steel brush. Only thing I'm really worried about in the whole system is the stupid adapter that goes into the wall thimble. It was supplied with the starter kit and it's stainless, but it's pretty cheapy. I'm sure I'm over thinking things.