I don't think the question was the problem. It was the square sisters answer that didn't make sense.
A: Until The cardboard biodegrades to the point that the chopstick limbs fall off.
A: Hatchi has no bones. He's all muscle. How else do you think he can carry around such heavy swords?
Q.(since it wasn't the one that wasn't answered) Luffy is rubber, Ace is fire. Has Ace ever melted a part of Luffy?