I have been in the process of DIYing a hammock sleep system (Silnylon tarp, down UQ, down TQ) when I stumbled upon this forum.  I have had a Surly CC  that I had hoped to outfit with racks & panniers... Until I checked out bikepacking.net, now I am really looking forward to going the bike packing route.  My question is would silnylon be an option for frame, handle bar, & or seat post bags to cut down on weight & add water proof properties, with the addition of polystyrene, styrene or something else to make rigid? Or would it not be strong enough to hold up long term?