David Daye did a masterful job of surveying available common materials, and putting them into service as lower-cost pipe parts. But there’s even more stuff available now than when he started. Is it possible to make a Do-It-Yourself bag without requiring leather-working?
I think it might be!
This bag is made with Thermoplastic Polyurethane (TPU). The black material is a lightweight polymer (plastic) that melts to itself when you heat it up with an iron. The white outside is some sort of nylon weave with TPU on the inside, providing more structure to things like airtight welds. You just iron the seams closed (with some parchment paper around it to protect your iron), there’s no sewing.
This prototype is much to small, but it’s holding air. To make it easier to work with, and to make the seams stronger as a result, I may square off the pattern, using only 45° angles and no gradual slopes.
It held up 10kg for about 30 minutes before it blew a leak. That’s okay: it was a pretty bad sealing job. But it proved that I can make airtight seals with this stuff, and it feels about right for a bag.