Most tactical gear that I’ve bought or seen is made primarily of Cordura. That’s a broad statement that requires a lot more detail.
For starters, Cordura is a brand name. It’s used somewhat generically to refer to woven synthetic fabric. The brand-name stuff is rayon but I’m pretty sure the off-brand stuff is made of other materials like nylon and polypropylene. It’s remarkably similar to canvas duck, which is cotton. As best I can tell, there is a long history of this stuff being used by the military, evolving from earlier cotton duck with the realization that synthetics can be woven tighter and carry better foul-weather properties. That is, it’s generally water resistant, even without a coating. It’s also tougher per unit weight, so the fibers have a higher tensile strength which means a thinner fiber will withstand flexion better than cotton. A thinner fiber of a synthetic is as strong as cotton which means thinner fabric for the same strength, which means less weight and bulk. Synthetic fibers are also glossy, which means that duck sticks and catches more than Cordura.
This fabric comes in different weights, like many fabrics. Unlike many fabrics, there is a good unit of measurement for its weight, the Denier, abbreviated D. (The unit D isn’t unique to woven synthetics but it’s very commonly used for them.) Some common weights are: lightweight, often in 10D, 12D, 15D or 20D; mid-weight pack cloth, often in 300D, 400D or 420D; and heavyweight (which seems to be where Cordura started out) at 1000D and 1050D. Clearly, the smaller the yarn (thread or filament used to weave fabric is called yarn), the smaller the Denier weight and the lighter the fabric. (Some units, like circular gauge, are reversed, where a smaller number means a bigger diameter; Deniers aren’t.)
Some woven synthetics are called ripstop. As one might expect, these fabrics are resistant to ripping. Specifically, they are woven with a pattern of thicker yarn at regular intervals. The general idea is that if the fabric were to rip, it would rip only up to the next thicker yarn in the weave, at which point the rip would stop. The thicker yarns also give the entire fabric a higher strength. Thus, ripstop Cordura is very often significantly lower weight for the same overall strength, with a 20D ripstop carrying the same general strength properties as non-ripstop in the 400D or higher range. Ripstop is more expensive than not, in general. Because it’s usually thinner, it is very often translucent than similar-strength non-ripstop. The pattern of the rip-stopping yarns can vary: in basic fabric it’s usually a 1/4″ grid with the normal weave but I’ve seen ripstop weaves across the bias and even decorative weaves, if you can call it that. Very heavy non-ripstop carries some similar properties as well: 1000D Cordura is tough and difficult to rip. I’ve seen high-Denier Cordura called ripstop without the reinforcing yarn pattern, which may be tangentially accurate.
A great deal of this sort of fabric is also laminated or coated. There is a difference between laminating and coating but the practical implications of one versus the other are complicated. A very common and inexpensive coating is polyvinyl chloride (PVC), which makes the material even more resistant to the elements. PVC-coated Cordura knock-offs are inexpensive and easy to obtain, and with the right treatment they can be used to make waterproof gear. You’ll know it’s PVC-coated if it’s got a soft, smooth, rubbery feel on one side. Other coatings vary in weight, how they affect the fabric, strength properties, weather properties, cost, etc. Another very useful property of most coatings and laminates is that they prevent or eliminate fraying of the fabric on unfinished cut edges. Synthetic fibers are slippery and tightly woven, so fraying can be a big issue otherwise. Webbing, especially, frays quickly and with surprising efficiency; with a subtle throw-back to Weezer, a length of webbing can disappear very quickly if you’re not careful.
There is nothing (globally) that says you can’t build tactical gear out of natural materials, like cotton, wool or silk. Your project requirements may dictate otherwise, and likely do. It’s tactical gear, so a pink flower print may not work well even if it’s IPX-7 waterproof and HOSDB KR3+SP3 stab resistant. There is more and more use of modular tactical gear for organization, where weight can be less of a factor, catching or pulling may be moot and color may be beneficial.
Lining & Padding
This is more of a personal endeavor, as I’ve come into contact with relatively little tactical gear that’s lined or padded. If it is padded, it’s generally fairly superficial.
From an engineering perspective, lining and padding are the same thing. They’re both one or more additional layers of construction material that would somehow change the properties of the primary material. The term, “lining,” generally refers to something on the interior side of a garment while the term, “padding,” refers to something between layers and completely internal to the garment. There are other similar garment-making processes that fall into the same classification: seam taping or finishing, reinforcement, stabilizing, structuring, etc. For simplicity, I’ll refer to anything like this on the interior or exterior of a garment as lining (including padding) and anything on the edge of a seam as finishing.
From this standpoint, to say that most tactical gear is unlined, is not precisely true: webbing is reinforcement and is very commonly in tactical gear. A great deal of tactical gear also has seams finished with seam tapes of various sorts. I contend that these, and some other padding or structure that’s common, are done with relatively little regard, except for finishing.
So why line? Here are some reasons why ordinary garments (not specifically tactical gear) are lined, with any garment’s lining often serving more than one purpose:
- Fashion. I mention this first because it’s one of the most common in anything made of fabric. This is purely form over function. The higher-end a garment is, the more likely it is to be lined in something that’s somewhat distinctive. I’ve had all my suits custom made for years and I always insist on a contrasting or patterned lining, because it looks good. Sure, few should ever see the inside of a gentleman’s suit jacket but consider that ladies often wear lingerie because knowing it’s there makes one feel different. There is relatively little fashion sense added to tactical gear, which is not a decision with which I disagree in the general case.
- Ease of movement. Good jackets and outerwear are often lined with slippery fabrics. Many dresses are as well, or the wearer is expected to wear a slip underneath. (A slip is essentially lining detached from a garment, similar to base layers or underwear.) This greatly eases putting-on and taking-off of the garment. It also adds comfort to wearing it, allowing the garment to shift slightly with the wearer’s motions. I think the former is of more importance with tactical gear although the latter may be in some circumstances. Most tactical gear is meant to be used, which means stuff moves in and out of it. This is completely analogous to putting on and taking off a garment.
- Structure and shape. The lining of a garment needs not, and sometimes doesn’t, match the exact shape of the outer fabric. A lining may assist the outer fabric in holding to a particular shape. Some types of lining (per my definition of the term), like stabilizer or padding, may actually be the primary cause of a garment’s shape, or part of a garment’s shape. Anyone who’s ever built a ladies garment that’s more complicated than a sundress and that covers her upper half knows something about this: the bodice, the part of the garment that covers the bust, generally has some shaping, which is often contributed-to by some sort of padding. Conceptually, if you’re not pulling against the contents of a garment — the wearer — and you’re not draping over it, something has to provide the underlying shape. This can be very important with tactical gear in the same way that ease of movement can be.
- Temperature and moisture control. Garments are usually worn by people (or other animals with the same general properties). Skin radiates heat and moisture. Anything close to the skin, like a garment, must take this into account if the wearer is to be comfortable. Expensive outerwear is often lined in breathable and wicking material, to move moisture away from the body. Truly, the primary purpose of outerwear, which is usually lined, is to regulate temperature. Also consider: swimwear, which promotes bidirectional transfer of moisture through it; a wetsuit, which regulates transfer of moisture and heat through it; and waterproof outerwear, which ideally prevents transfer of moisture through it. Some advanced fabrics, like Gore-Tex, are engineered to allow unidirectional flow of moisture — no water in, all perspiration out — while selectively regulating heat transfer. A lining must assist primary fabric in this function, or enhance it. This is critical in the design consideration for most tactical gear.
- Wearer protection. Temperature and moisture are just two of the physical conditions to which a garment alters the wearer’s reactivity. First consider the gear a baseball catcher wears, how it protects the wearer from the impact of an errant baseball travelling at high speed and other physical impact. Then consider the fact that a bulletproof vest is nothing more than a vest with added protection from impact-resistant materials, traditionally aramids like Kevlar and ballistic plates. To design most tactical gear without considering this borders on folly.
- Garment protection. Garments rightfully are expected to be durable. Fashion garments tend to be minimally resistant to external stress, such as abrasion. A lining can help to protect from internal stress, such as wear from repeated movement. High-end jeans, trousers or slacks have lining to protect the garment from the wearer: sweat stains and also abrasion of the inside of the garment fabric from constant rubbing. Tactical gear, which often involves repeated motion such as insertion or retraction of gear, can benefit from this sort of protection to increase its longevity.
To sum this up, a lining enhances properties of the primary external fabric of a garment. Good tactical gear can be made better with careful selection of lining materials to suit a particular requirement in the same way that a good lining can make an ordinary garment better.
One may build tactical gear out of other materials as well. A normal tactical gear project needs a good number of different kinds of notions. These will be covered separately.