Pure fiberglass? Pure fiberglass is not a casting material. Fiberglass gets it's strength from the resin that laminates it. Urethane is a non-reinforced resin that does not require reinforcement because it is more impact resistant. I don't think anyone here has impact tested these two materials to prove which is stronger. Properly applied fiberglass resin composite is tough as nails... have you guys never seen a fiberglass hammer handle?
Pure fiberglass? Pure fiberglass is not a casting material. Fiberglass gets it's strength from the resin that laminates it. Urethane is a non-reinforced resin that does not require reinforcement because it is more impact resistant. I don't think anyone here has impact tested these two materials to prove which is stronger. Properly applied fiberglass resin composite is tough as nails... have you guys never seen a fiberglass hammer handle?