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Materials Deep Dive: The Freefly16

September 30 2019

Materials Deep Dive: The Freefly16
Materials Deep Dive: The Freefly16
With all the options on the market these days, sometimes it feels like you need a PhD in Gear just to find the right backpack for your needs. We asked our Product Designer, Sam, to break down some gear terminology so you can find the right backpack for you, and impress your outdoorsy friends with new words like "denier".
As a consumer my favorite part of purchasing something new and shiny is researching the specs and materials beforehand. Often, I find myself frustrated with the lack of useful info available on a company’s website. I'm here to help break down some of those specs with a deep dive into our product descriptions. Up at bat this week is the Freefly16.

“Waterproof 30D Cordura® ripstop nylon”
  • In this case when we say “waterproof” what we really mean is that given the intended application, this highly water resistant fabric will keep your stuff dry.
  • 30D is shorthand for 30 denier. Denier is technically a measure of the weight of the yarns that comprise the fabric. In real world use denier roughly correlates with how burly the fabric is. Classic, heavy duty 1990s packs were often made of 1000D fabric. 400D-600D is the standard backpack weight, probably what your school backpack was made out of growing up. Ultralight backpacking packs often range from 100D-210D. 70D and below are usually tent or jacket weight fabrics. The Freefly16 is made of 30D fabric, which is how we got it to pack down so small. The trade off is that it’s more delicate than bags made from thick fibers, but we use the highest quality 30D fabric available to account for some of the difference. Read on for more details on that.
  • Cordura is a popular, industry-leading fabric manufacturer. They make some of the highest quality fabrics around. They’re best known for their 1000D nylon.
  • Ripstop refers to how the fabric is woven. Woven fabric is made up of yarns that are often arranged at 90 degree angles to each other and interlocked in an over-under configuration. A ripstop weave is a technique where a heavier and stronger yarn is interspersed in the weave. Visually, this creates a grid pattern, but functionally–as the name implies–this heavier yarn will stop a rip from spreading. Think of putting a strip of tape down the center of a piece of printer paper and then tearing the paper in half… the tear will likely stop when it hits the tape.
  • Nylon is a type of plastic, invented by DuPont in the 1930’s. Historically the two competing outdoor fabrics have been Nylon and Polyester. Nylon is stronger and more expensive than polyester, but polyester is more UV resistant and doesn’t get a soggy, stretchy feel when wet like Nylon does. Not all nylons are created equal… the vast majority of backpack nylon is of a molecular composition called Nylon 6. Our Freefly16 fabric is Nylon 6 6, which has a significantly higher tear strength. This is one of the reasons why we can use such lightweight fabric in a backpack.


“Siliconized waterproof coating”
The waterproof coating on our Freefly16 is actually silicone on the face and polyurethane on the backside. Our testing shows that this combo gets the best of both worlds. Silicone coatings feel slick and slippery to the touch, and while they increase the strength of the fabric, they aren’t actually the coating that makes the fabric waterproof. Instead, the slippery silicone makes the fabric shed water quickly so it isn’t absorbed by the nylon fibers. Polyurethane coatings often feel sticky and tacky to the touch, this is the coating that makes the fabric waterproof. Unlike silicone, PU coatings decrease the tear strength of the fabric slightly and can fail by delamination over time due to prolonged exposure to heat or moisture. This is why you need to let your bag dry before you pack it up. While it has some slight downsides, polyurethane is still the best choice for waterproofing on most fabrics.
“Internally sealed seams”
This is one of the features we’re most proud of. Many backpacks use waterproof fabric, but very, very few go the extra step of taping the seams. The idea here is that when you construct a backpack, every time the sewing needle punctures the fabric, you’ve created a hole for water to pass though. After the Freefly16 is constructed, a clear tape with a heat-activated adhesive backing is applied to every seam on the inside of the pack. This seals up the stitching holes so even in a rainstorm, your gear stays dry.
“Water resistant zipper main compartment”
Most zippers are opened and closed by operating a “slider” which runs on a track or “coil”, sewn to a fabric strip called “zipper tape”, which comes on a long roll and is cut to length and installed in the backpack during construction. The zippers we use have the coil facing inwards, and have a polyurethane coating over each side of the zipper tape. When the zipper is closed, the PU coatings on the zipper tape meet in the middle of the zipper and form a seal to keep water from penetrating the zipper. This type of zipper is not meant to be forcibly submerged and isn’t appropriate for a scuba diving application, but is – in our opinion – the cream of the crop when it comes to weather protection in an EDC backpack.
“16 liter capacity”
This is a measure of the volume of the backpack. 16 liters is equivalent to 976 cubic inches. When you read “16 liter capacity” on our website, think “small daypack”. And yes, you can pour 8 two-liter bottles of Pepsi into this backpack, though we don’t recommend it... we recommend Coke.
“Front organization pocket with water resistant zipper”
We’re of the opinion that even the lightest, most packable, most minimalist backpacks need a zippered pocket for essentials.
“Adjustable, weight distributing shoulder straps”
Because non-adjustable shoulder straps on packable bags are a thing… but not a good thing. When we say “weight adjusting” what we mean is that we went to great lengths to find a mesh material that is stiff and structured enough to hold its shape and not collapse under the weight of the backpack. In real-world use, our 2.5” wide shoulder straps maintain their 2.5” width instead of collapsing to a thin, string-like strap that digs into your shoulder.
“Non-absorbing shoulder straps”
Some shoulder straps absorb water and then wring out like a sponge when you put on a heavy backpack… ours don’t.
“Detachable, rolltop storage bag – optimized for fast pack up”
The rolltop acts as compression, so that we can slightly oversize the bag for ease of use, but still end up with a tight, compact package for optimal stowability. Plus, when the backpack is in use, the storage bag is the perfect size for essentials like keys and jewelry.
“Available in Charcoal Grey and Coyote”
Fancy names for juuuust the right shade of grey and brown. We love the colors and we think you will too.


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