Went to his house last night and checked on the grenade. After carefully checking it we decided it was not hard enough (still bends) so we're going to try to get some Fiberglass Resin.
Ok used Fiberglass Resin on a small piece of grenade. It is about 100 times harder than the Urethane! And that was just the first light coat! Excited to Fiberglass my boots soon!