That's interesting! I think of butyl rubber as being fairly expensive stuff compared to building materials—here on Earth, construction sand costs maybe 4¢ per

That's interesting! I think of butyl rubber as being fairly expensive stuff compared to building materials—here on Earth, construction sand costs maybe 4¢ per kilogram, while polymers typically cost around 200¢ per kilogram. I'm not sure how much to expect that higher cost to transfer to Martian and asteroid ISRU, because I don't really understand where it comes from. Are you thinking that the composite you're describing would have major advantages, even if it's more expensive?