I built a heavy pvc tube precisely for sending rods. I've shipped it from Ohio to South Carolina, Wisconsin and north Carolina several times with no issues. I bought the heaviest pvc, schedule 80 I think, that they had at home depot, put a solid cap on one end and a screw closure clean out cap on the other. I put 4" thick heavy foam in the closed end and glued it in place. I bubble wrap the rods so they can't flop around and put one or more pieces of the same foam in behind them to fill the space to the opening cap. I think it cost about $35 to build, pvc, caps, foam and glue. After I close it up, I tape over the clean out cap to make sure it will stay closed. It may be overbuilt, but it has got the job done.