I have a gas bottle welded to a 3 inch pipe stove. Could get away with 2.5 inch.. but any smaller and it will need to be cleaned regularly unless your
wood is perfect. 3 inch is optimal because it never needs
cleaning. By the looks of the
corrosion over 9 months, it probably has 2-3 years. At that time a new one could be made. It took a day to build (by a very person who helped me) but cost nothing.
If you want longer lasting, try stainless, or thicker pipe and tank.. although since I am using standard gas bottle it might be difficult to find thicker.
I use this most days, especially during cold or rain as it seems to turn the rain "off". Can insulate the walls using ash with an inner metal liner to improve efficiency.