Rod Blank
From The Angler's Dictionary — your encyclopedia of fishing rods, reels, and tackle
The rod blank is the long, tapered shaft that forms the structural core of a fishing rod. It is the most important component, determining the rod's power, action, sensitivity, and weight. Blanks are manufactured from graphite (carbon fiber), fiberglass, or a composite blend of both materials. Graphite blanks are lighter and more sensitive but more brittle, while fiberglass blanks are heavier and more durable with a slower, more forgiving action.
Blanks are constructed by wrapping sheets of material around a tapered steel mandrel, then curing them in an oven. The modulus rating of the graphite — measured in millions of pounds per square inch (MSI) — indicates stiffness. Higher modulus graphite produces a stiffer, more sensitive blank but can sacrifice durability. Common modulus ratings range from 24-ton (moderate stiffness, good durability) to 46-ton or higher (extremely sensitive, more fragile). A rod's quality is largely defined by its blank — guides, handles, and reel seats can all be upgraded, but the blank is the foundation.