Carry Geeking | Cordura Fabric
Years ago I asked a major bag maker what his single best tip was for making a great backpack. His answer? Good fabric. He said good fabric meant everything goes together better, with fewer tricks and cover-ups needed.
So when the folks from CORDURA® started to drop comments on one of our posts, we figured we should ask a little more about what makes a good fabric. Enter Allen Mortimer, global product manager for Cordura brand…
Carryology: Do you have tips on choosing good bag fabrics versus bad?
The key to choosing the right fabric for a bag is to simply try and match the requirement to the offering – so keep the end use in mind. Will it be for hiking, climbing, or something less intense? Weight is not a major concern for day-to-day usage such as visiting the mall, going to school or the grocery store, so a CORDURA Classic (80-1000 Denier Nylons) or CORDURA HP (300-530 Denier Polyesters) fabric construction would offer a versatile and durable solution. However, for technical bags, such as those used for long hiking treks in the outdoors, it’s critical to have a lightweight construction for comfort, load control and durability. For example, many technical packs use CORDURA Lite (210-630 Denier) fabrics or CORDURA UltraLite (30-100 Denier) fabrics, which can be constructed of lightweight nylon pack cloths, rip-stops and dobby weaves that offer stylish durability and optimal strength-to-weight ratio. This fabric is resistant to tears, scuffs and abrasions.
2. Could you provide some information about the industry shift away from PVC backings and how new options stack up?
Polyvinyl chloride (PVC) is rarely, if ever used except for in the cheapest, lowest grade backpacks [Ed's note: There are still way too many bags in this category]. Currently, you would not see that type of backing in any reasonably priced daypacks, technical packs or even luggage. PVC backings are very heavy and typically a lamination that is heat-sealed. PVC in Europe is highly regulated due to environmental concerns in making and applying the PVC.
An alternative, and more commonly used back coating is polyurethane (PU). PU is a lighter weight backing and provides optimal durability in fabric. [Ed's note: PU backings are sprayed on rather than laminated like PVC's. The more coats of PU you make, the thicker and more structured the fabric feels].
3. How does the often overlooked tightness of weave affect strength and durability with bag fabrics?
The denser the fabric weave, the heavier it’s going to be. The optimum blend construction depends on strength-to-weight, durability and water resistance. Tear resistance can be adversely affected when stiffening the fabric. The more ends and picks in the fabric, the more abrasion resistant. However, if the fabric is woven too tightly with too many ends and picks, a cross over happens and the fabrics begin to decay. (Picks are the yarn ends that go across the fabric. Ends go down the length of the fabric. The number of ends by the number of picks helps classify the fabric construction. Ex: 60 ends by 60 picks per inch is a square cloth.)
For example, when fabric is torn, the ends tend to bunch. The ends and picks try and resist the tear. Fabrics can become too stiff when a heavy coating is applied or weaving is so dense that the fibers cannot move. Either of these constructions may cause fibers to resist and prevent them from bunching in groups, therefore resisting the tear in singular fashion, which tends to reduce the tear resistance.
So there you go, a bit of a dive in to fabric geeking care of the good folks at Cordura.
Were there other questions that you guys wanted to ask? Things that will help you design or select the best bags in the world? We’ll be able to follow these questions up with more in the future, so drop some comments with the juice you’d like to discover.