To repair a ~6" (~150mm) line of pinholes in a NeoAir camping mattress, what is the best repair material?
The line is too long, and the pinholes too close to each other, to use standard or emergency Thermarest patches.
I’m hoping for a solution that will last as long as the sleeping mat, and won’t significantly impair its packability.
Use multiple patches. You can also get patch kits made for bicycle inner tubes but the patches are thicker. The self-sealing kind are the easiest to use. On the other hand it’s possible that they don’t stick as well as the ones that come with a tube of glue. I say this because I used one on my bike recently and the tube still leaks and I’m weirdly having trouble finding a replacement tube.