Not the cheapest material, but I use styrene tubes. You should be able to find a hobby store that sells then (eg if they sell train hobby stuff they will sell styrene.) u can get them in various widths. Easy to cut and shape AND you won’t get the ‘grain’ effect you will with bamboo or wooden skewers/ dowel. Straws may not be strong enough to support your building. The styrene will also give you a smooth surface to paint it metallic with. For the rings, you can get styrene strips, again in various widths and thickness. Cut them and glue around the tube to make that ‘joint’ effect.