I'm going to be working on a project soon that uses very, very large smoothbore plastic pipe. It needs to be 24-27 inches in diameter, smooth on the inside, and not too incredibly heavy. It'll be under a slight vacuum. I've been looking at the green PVC sewer pipe, which is supposedly available in those sizes, but it's not going to be easy to get. Apparently it's not used a lot for some reason. It is very important that the inside be smooth and pretty consistent in diameter. Does anyone know where I should be looking or if there is anything better for this application?
Metal content: Remaining components of this project will be made of mild CR steel, and aluminum, mostly 6061. Wiring most likely made of copper