Pack Cloth

The quality of pack cloth is generally (but not always) reflected by the thickness of its fibers. Thicker fibers tend to be more durable and abraison resistant. But newer, lighter fabrics, that incorporate tear and abraision resistant processing allow, lighter materials to be used for some applications. The thickness of fibers that make up a particular cloth is expressed as denier. The higher the number, the thicker, heavier, and more abrasion-resistant the cloth. For example, super-light nylon taffeta used in sleeping bags measures between 20-40 denier. Most pack cloths begin at 420 denier. The higher the denier the stronger the material but this also leads to heavier overall pack weights.

Rapidly becoming one of the most popular fabrics in premium packs, Dupont-made Cordura comes in 500 or 1000 denier fibers. Unlike standard 500 or 1000 denier nylon, Cordura undergoes additional processing to increase the tensile strength of the fiber (increasing abrasion and tear resistance).

Pack Frames and Suspension

Suspensions feature aluminum stays, delrin rods, polycarbonate and high density polyethelene (HDPE), and even carbon fiber weaves. Aluminum comes in a variety of weights and alloys for different characteristics in flex, stiffness, and load bearing ability. Polycarbonate is usually featured as an impact resistant plastic, and as a base for framesheet materials. Delrin and carbon fiber are both featured as stays, frequently in conjunction with polyethelene sheets. Delrin is a torsionally rigid but bendable composite used to stabalize large loads in big packs. Carbon fiber is used to the same end but is lighter, stiffer, and more expensive.

Two types of foam exist in the pack world, open-cell and closed cell-foam. Open cell foam (like the remenants of a bunch of exploded bubbles) is usually lighter and provides a softer feel in cushioning, while closed cell foams (structured with the air bubbles intact) provide a firmer ride. To many it's simply a matter of personal preference. A variety of foam densities are used in pack harnessing depending on pack weight and application. Be sure to research factors like breathability, particularly when choosing a pack you'll use in hot or humid conditions. Packmakers frequently apply treatment finishes to their foams to prevent mildew, bacterial growth, or UV degradation. A nice extra to look for is a wicking fabric on a harness system.

Pack Accessories

The newest material in the pack world is DuPont Hypalon. Borrowed from the whitewater industry (used on raft bottoms), Hypalon is cut from sheets of rubberized, laminated nylon. Hypalon protects areas that come into contact with puncture inducing items such as crampons, ice axes, snowshoe cleats, ski, and snowboard edges.

Other key materials used in pack making include Kevlar or Dacron thread and heavy duty YKK nylon zippers. Kevlar and Dacron both YKK is the zipper supplier for technical garments, tents, packs, bags, and accessories. Start looking at your zippers at home. More often then not it says YKK. These zippers come in a variety weights and sizes, with larger model numbers indicating beefier zips. YKK zipper hardware is made from smooth pulling nylon and the pulls are nickle plated for low resistance. There is a weight trade-off with smaller guage zippers, but avoid ones with extremely fine teeth or plastic pulls that get brittle in the cold.