#HTE

Tutorial: How to Create Tough, Lightweight and Waterproof Gear Bags From Dyneema and Tyvek

In this tutorial, I’ll show you how to make a variety of useful zippered gear bags that are incredibly tough, lightweight and waterproof.

This tutorial is intended for someone like me: familiar with rapid prototyping tools like 3d printers and laser cutters, reasonably competent with hand tools, but pretty clueless about sewing and sewing machines beyond emergency repairs and hemming the odd pair of pants.

I promise that after less than an hour of trial and error on a sewing machine, you’ll be able to create out an endless variety of useful stuff. Making clothes on a sewing machine is HARD. Banging out awesome gear on a sewing machine is EASY.

If like me you come from working with additive or subtractive rapid prototyping processes, you will discover that fabric has all kinds of mind-bending topological properties, meaning you can fold, scrunch and invert it in ways that allow you to conceal your sewing ineptitude.

We use some fancy gear—including an electric hotknife and a heavy-duty industrial sewing machine—but mostly to save time and labor. With a little persistence and creativity, you will be able to reproduce almost all of our steps with even the most basic sewing machines. If you want to have a bag right this instant, we are also offering some as rewards for supporting our Kickstarter campaign.

NOTE this tutorial is a draft! Help us make it better by putting your suggestions in the comments!

Step 1: Three Basic Gear Bag Designs

There’s little novelty in basic bag design—once you understand the archetypes, you’ll see them everywhere (and after you make a couple yourself, you’ll be shocked by the prices). After some experimentation, we’ve identified our three favorite bags.

The flat top-zipper case is useful as a pencil case, for wrangling snarls of USB charge cables and for protecting a passport and plane ticket from sweaty pockets and tropical downpours.

The flat front-zipper case works as a document holder, a case for chunky gear and as a waterproof/bugproof sleeve for travel-size laptops.

The duffel bag is perfect for keeping work clothes dry on your bike commute, as an overnight bag on short trips and as a bug-out bag for doomsday fantasies.

In general, I avoid projects that require lots of sewing skill because I have none. I’ve found that size and detail are the key variables: a small wallet with lots of little pockets is a nightmare. A giant set of drapes can be a hassle to feed through the machine unless you have an equally gigantic work surface. Our three favorite bags offer high utility and low fabrication complexity. I find the flat front-zipper case to be the easiest to build, and the duffel bag the most complex.

Step 2: Materials

FABRIC

We make all of our field research gear bags out of Dyneema (brand name of ultra-high-molecular-weight polyethylene, aka UHMWPE or UHMW, also sold as Spectra and cuben fiber). Dyneema is a composite material that is roughly twice as strong as Kevlar at half the weight. William Gibson described Dyneema as “sort of like if NASA made waxed paper.” Popular with both high-performance sailmakers, ultralight hikers and the military, Dyneema is UV-resistant, tear-resistant and 100% waterproof. I bought a cuben fiber wallet in Hong Kong five years ago and after loads of abuse it still shows hardly any wear.

For the exterior of all the bags, we use a single layer of composite fabric, with a shiny inner lining of 48 g/m^2 Dyneema bonded to a matte outer layer of 50 dernier polyester. We’ve only found this material in grey and black. As far as fabric goes, Dyneema isn’t cheap but a home-made bag will cost a fraction of a similar factory-made bag from Your Favorite Outdoor Company.

For the middle layer of the duffel bag, we use 62 g/m^2 Tyvek, the same material used in your home’s vapor barrier, in tear-proof envelopes and in a million DIY wallet and kite projects. Tyvek is stiff and folds like paper, so helps the duffel bag keep its shape. Tyvek is hard to rip and relatively puncture-resistant, but it will pill up and get tatty over time if it gets a lot of wear.

For the duffel, we sandwich the Tyvek between the outer layer of Dyneema composite, and an inner layer of thin and nearly transparent 34 g/m^2 Dyneema. The thin Dyneema lets you see the Tyvek logo, which is useful for hipster cred, and in general makes for a bright bag interior that makes it easier to find stuff. We’ve recently started experimenting with replacing the inner Dyneema layer with mustard-yellow Robic XL ripstop nylon.

OTHER MATERIALS

- We assemble the bags on our industrial sewing machine using bonded polyester outdoor thread that is resistant to UV, heat, abrasion, salt water and mildew.

- We use YKK Aquaguard water-repellent zippers, #3 zippers on the small bags and #5 zippers on the duffel.

- We give the bags additional waterproofing by sealing all of the internal seams with single-sided Dyneema seam tape.

- For handles on the duffel bag, we use 2" nylon webbing. Many vendors sell really coarse webbing that’s tough to fold and sew. The softest webbing we’ve found is Sailrite’s 1800# nylon.

- For the duffel bag strap, we use bright red ¾" tubular nylon.

- For the zipper pulls, we use fluorescent yellow 1.2mm Dyneema line.

- We use ¾" and 1" binding tape (grosgrain ribbon) to create zipper stops and loops

- The key to speedy assembly is “basting tape”, a kind of heavy-duty double-sided tape that’s used in making sails and awnings. We use the basting tape to attach things together before we sew them, for example the zippers and the Dyneema, and the fabric layers of the duffel bag. Everyone who actually knows how to sew seems to think that basting tape is tool of profligate degenerates. I like not stabbing myself with pins.

SOURCES

- Zpacks and Ripstop by the Roll fabric and some of our zippers

- Sailrite for polyester thread, basting tape and other zippers

Step 3: Tools

MEASURING, MARKING AND CUTTING THE MATERIAL

- grease marking pencil (for marking cut lines)

- tailor-style fabric tape measure

- two- to three-foot straight-edge for tracing lines

- OPTIONAL: a 24" quilting ruler (much easier to make measurements off the edge of fabric, as the transparent ruler smushes the fabric flat)

- electric hotknife and a glass or metal plate (heat resistant cutting surface)

- OR rotary cutter, a self-healing cutting mat and cut-safe gloves

- OPTIONAL: an electric rope cutter (useful but not necessary for cutting and automatically fusing zipper tape and nylon ribbon)

Having blunted a whole collection of rotary cutters on Dyneema panels, we looked for alternatives. We did some experiments cutting Dyneema sheets on our laser-cutter, but given the simple designs of these bags and the hassle of fabric flapping around in breeze generated by the laser ventilation, it seemed like overkill.

We now prefer to cut the material with an electric hotknife. If you are going to cut Dyneema with a rotary cutter or something like a box-cutter or an Xacto blade, I strongly recommend you get a pair of cut-safe gloves.

We invested in an electric rope-cutter a few years ago for cutting and instantly fusing the ends of paracord, nylon webbing and dyneema line. For such a weird specialized gadget, it gets a surprising amount of use in the studio.

SEWING

- a needle threader (who knew you didn’t have to fish around trying to thread the needle for ages)

- a chopstick (for pulling thread from the lower bobbin, and gently poking out corners when you invert your bag)

- thread snips (worth having; more convenient than scissors and you’ll be cutting lots of dangling threads)

- a seam ripper (for unwinding mistakes)

- basting tape (we prefer Seamstick ¼" Basting Tape For Sailmaking & Vinyl)

We use a Sailrite LSZ-1 sewing machine. We really only need the walking foot, the powerful needle and the zigzag stitch when we’re sewing the handles for the duffel bag. It should be possible to build the two smaller bags on any sewing machine.

Step 4: Cutting the Material

CONSIDER STOCK DIMENSIONS

The vendors we use carry 54" wide rolls of Dyneema, and they sell it by yard. That means you get 54" wide by 36" sections (or longer in three-foot increments). Tyvek comes in 108" wide rolls and they sell it by the foot. The Robic XL nylon comes in 68" rolls and they sell it by the yard. All of our vendors send the material folded up in a box rather than wound around a roll.

Our first step in bag design is to set the dimensions to minimize waste. As the most expensive material, the Dyneema roll dimensions determine our bag dimensions. In the beginning, I tried all these fancy formulas for dimensions, setting target internal dimensions for the bag and then working backwards to include seam allowance and other factors—but I’m too sloppy at cutting and sewing and this isn’t press-fit cabinetry.

Now, I simply divide the 54" roll width as follows for each bag:

pencil/passport case

- Goal is to cut panels that are 9" wide by 10" tall

- Cut a 10" tall strip off the roll,

- Cut that strip into six 9" x 10" sections

- Creates a flat case that is roughly 9" wide by 4.25" tall.

document/laptop case:

- Goal is to cut panels that are 18" wide by 21" tall.

- Cut a 21" wide strip off the roll

- Cut that strip into three 18" x 21" sections.

- Creates a flat case that is roughly 16" wide by 10" tall.

duffel bag:

- Goal is to cut panels that are 27" wide by 36" tall.

- Cut the 54" wide by 36" stock section in half to create two 27" x 36" sections.

- Creates a bag that is roughly 10" wide by 18" long by 7" tall.

CUTTING THE MATERIAL

Our favorite way to cut with the hotknife is to use the large flat metal engraving bed that came with our laser cutter. We pin the dyneema sheet down on top of the metal plate with magnets (magnetic pin backs from conference badges) and then quickly zip the hotknife along the marked line. For a heat-safe cutting surface, you can also use a big pane of glass.

After I’ve cut the exterior Dyneema panel for the duffel bag, I cut the Tyvek middle layer and and the interior panel of Dyneema or nylon slightly big. I find the most square edge of the outer Dyneema panel, and attach it to the most square edges of the Tyvek and inner material layers with double-sided basting tape. I lay the composite panel flat on the metal engraving bed and trim away the excess with the electric hotknife.

Step 5: Prepare the Panels and Attach the Zippers

ADD PATCHES

Starting with the blank panels, consider whether you want to add any patches or nametags—as it gets much harder to do once you attach the zippers.

For example, I found dozens of vendors selling inexpensive military “name tapes”, a narrow embroidered fabric name tag that can typically fit a dozen letters or so. They come in all kinds of colors, from the most stealthy camouflage patterns to ninja black-on-black to color patterns that are easy to read from far away. We went with the white letters on navy blue ripstop nylon.

Another relatively inexpensive way to personalize your gear is to invest in a custom woven labels. I designed the label in Adobe Illustrator in the “center fold woven label” style so it would have our logo on the front and a short message on the reverse. I saved the file as an EPS. Wunderlabel charged US$100 for 300 labels (one hundred labels would have been just a few dollars cheaper) and delivered the labels in a couple weeks. I didn’t have time to do much price-shopping so there may be cheaper service. Anyways, it’s amazing how a little tag turns a home-made bag into an official Real Thing.

Embroidered tag

Military-style nametapes

The steps for attaching the zippers are as follows:

1. Mount the zipper slider on the zipper tape. This can be tricky, especially with the tiny #3 zippers. See the video for a quick HOWTO.

2. Cut the zipper tape to length with a half-inch margin on either end

3. Create stops on either end of the zipper by sewing folded pieces of binding tape across each zipper end. Make sure the opening of the fold faces the outer edge of the zipper.

4. Attach one edge of the zipper to the panel with basting tape using an inside-out fold.

5. Zipper sewn in place.  Note that the shiny side in the inside surface of the bag. 

6. Flip over and fold the Dyneema fabric down.  Now you see the outside of the zipper and the outside of the bag.

7. Place a strip of basting tape on the outside of the zipper.  Note that this shows the paper backing on the basting tape.  Remove the paper backing (duh)!

8. Fold the bottom of the Dyneema up onto the basting tape.

9. Add your embroided label between the Dyneema and the zipper before you sew.

10. Sew across the attach the zipper.  Now you have an open-ended tube of Dyneema with a zipper on top.

11. Showing the other side.

12.  Side view of the inside-out bag with the zippers attached.

Step 6: Sew the Sides to Complete the Flat Top-Zipper Case!

Attaching the zipper is the hardest part of the basic gear bag. Now you simply need to cut some loops out of binding tape for the side of the bag, and stuff them inside the fold along the unsewn edge of the bag (see video). Then you run a stitch down each side of the bag.

Inside-out bag, showing the zipper tab sewn in place.

The finished bag!

Flip the bag inside out. Create a zipper pull—we use bright yellow thread. You’re finished!

For extra credit, you can tape the seams on the inside of the bag with single-sided Dyneema tape to make the bag waterproof!

Step 7: Stay Tuned!

Next, I’ll add instructions for the flat front-face zipper bag, and the duffel bag.  Check for updates here on Core77 or on DtM’s Instructables project page.

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This “Design Experience that Matters” series is provided courtesy of Timothy Prestero and the team at Design that Matters (DtM). As a nonprofit, DtM collaborates with leading social entrepreneurs and hundreds of volunteers to design new medical technologies for the poor in developing countries. DtM’s Firefly infant phototherapy device is treating thousands of newborns in 21 counties from Afghanistan to Zimbabwe. In 2012, DtM was named the winner of the National Design Award.