The fishing rod is getting softer and softer. How to harden?

The process that the fishing rod becomes softer and softer is irreversible, so it cannot be hardened by physical methods. It can only be changed by coating hard paint on the fishing rod or wrapping a layer of plastic foam on the lower part of the fishing rod to increase the hardness.

Fishing rod is a fishing tool, slender and jointed, usually with a handle, and a fishing line is used to connect the hook and bait. Fishing rod was originally a tool for human beings to make a living by fishing, and now it is usually used for outdoor sports.