User blog comment:Mathmagician/Wall of Flesh Solo Guide/@comment-4691107-20111219002846/@comment-4674838-20111219011443

It doesn't really matter too much what you make the bridge out of, I just personally prefer wood platforms and happened to have a large forest nearby. If you want to start building the bridge right after you finish your hellevator, it also makes a lot of sense to use the dirt/stone in your inventory.