Stale bread does not work as an armature. It failed at a chemical level.
I used stale manchet bread, as this is the type of bread that would be available to a wealthy household in 16th century England. Sugar was rolled to 1/16″ of an inch and sealed around a shield shape of stale bread 1/2″ thick. It was allowed to dry with the other samples created for the A&S event. By the second day, the sugar had cracked and started to ooze some sort of substance.
This had the appearance of a modern royal icing. By the time of the event 5 days later, the ooze dried to a hard crust. But flakes of paste started to flake off. The flakes were paper thin and sticky. The bread underneath had a glazed appearance and was also sticky. The consensus of the folks who say the end state was that the carbohydrates in the sugar and bread, were competing for “resources.”
This was a neat failure at the chemical level. However, it makes for a very poor substance to use as an armature. This will be the last time I use this medium as an armature for sugar paste.