I discovered today that creosote build up happens to an outside pipe whether it is single double or tripple walled.The double wall pipe allows for closer clearances to combustibles ,especially if the inter air space is filled with a fire clay or wool.
There is a gye on utube who makes his own with a 1 in. air space. He puts 6 inch pipe inside 8 inch held apart with metal tabs pop riveted.
Yes it is 8x8 square and @ 15 feet high for a look out in the loft which doubles as a second floor. 4 4x6 14 foot poles 2 feet in the ground mortice and tenon construction also called post and beam.
Ther is a place outside of town that ,in the late 19th Century , was located a clay deposit that,when assayed in Seattle was found to be fire clay which doesn't burn and which supplied bricks all over the world when things were steam and they needed to line their boilers..I think I'll go out there and see if I can locate it so as to custom make any shapes I need for the project. I recon I could ontact some excavation companies in the area who are digging or inquire at the City Hall Museum about the former operation and just where the deposit was.
you should have said you wanted to do this the hardest way possible when you first posted.
