When I build rods and ship them I use this pipe from lowes - it's a thin-walled PVC to save on weight:

https://www.lowes.com/pd/Charlotte-Pipe-1-1-4-in-x-10-ft-160-PSI-PVC-Pipe/3133113

A pair of 1.75" black vinyl end caps and a drinking straw folded over the end of the pipe and under the cap to release the pressure as mentioned and you're in business. Tape the caps on but don't cover the end of the straw with the tape.

Won't work for spinning rods, too high a guide height, but for casting rods or fly rods it's great.