Drynamic Bag Creation
Building the First Prototype
I’ve described this project in previous posts, but these illustrations give an overview of the concept
Early this year, I interviewed an industrial designer, Ryan Lee, to discuss his soft-product design expertise and career making backpacks for top outdoor gear companies. During his talk, he mentioned that some designers use chicken-wire to construct the shape of their bags in early-stage prototyping. I thought that was an excellent idea for the odd shape I was trying to construct.
I purchased cheap cotton then cut, pinned, and marked it on the chicken wire shape to start understanding how fabric can be manipulated into this shape. I cut the fabric in ways that I thought would be easiest to understand and reconstruct. I drew out the dimensions and then traced the shapes onto my actual bag material.
The fabric I was using to construct the bag was Heat Sealable 200 Denier TPU in Marine Safety Orange. It is water-proof, resilient, and can be heat-welded together to create a super-strong bond. On one side, there is a synthetic woven fabric feel and on the other side is a soft-plastic that melts. Putting the soft plastic sides together and then using a heat-welding iron melts them together. My method was to line up the edges and weld strips underneath to seal them together.
I created one prototype and was satisfied with the shape and what I learned with the methods of heat welding. There were tiny holes at the corners and along some seams and I thought that I could fix those with another prototype. Additionally, with this shape, I could create a better pattern by strategically cutting it apart. I cut this bag, traced the updated pattern, and started making another prototype.
In my next attempt, I used wider and longer continuous strips to heat weld the seams together. This helped me to limit holes between the seams and to better predict where holes might occur. I attached a D-ring to the front, a roll-top buckle system to the back, and the inflation tube to the top. I used an epoxy seam-sealer to stop up tiny holes and ensure it was totally airtight.
I abandoned the backpack straps and plastic window for the light because they aren’t necessary to test in this first prototype. When I see that the bag floats appropriately with weight then I will start testing those additional features.
This project was humbling and challenging. The materials and tools took patience to understand and practice with. The shape was tricky to achieve and I still believe that mastering a CAD program to create this shape and “unroll it” into a pattern is the way to go.
For my next steps, I need to get this bag in the water with some gear and give it a test. Unfortunately, the lakes are frozen over and the CU pool has been shut down, so I’ll need to wait a bit. I can continue working on the website and thinking about other applications this bag could be used for as a product. I am thinking about using this bag for one purpose, but thinking about other uses could open up new markets.
For example, when backpacking I often run into rivers or lakes that I need to go around or find a bridge crossing because I can’t cross with a backpack. With this product, I could put my gear into it and swim across a lake or river. An alternative for river crossings is I could put the gear inside this bag, tie a rock to parachute line, heave the rock across, swim to the other side, then pull the gear across using the line.
