Are Iron/Brazen/Silver Signs destroyed upon failure?

[RoboEmperor]

It only says it's destroyed if a successfully bound creature is released from the binding.

Does this mean I can endlessly replace a silver sign as a full round action until it succeeds?

Edit: These are special items crafted by the Nar Demonbinder class.

[Zaq]

Those aren't familiar to me. What book are they in?

[RoboEmperor]

Those aren't familiar to me. What book are they in?

Unapproachable East, the PrC Nar Demonbinder has exclusive access to those items. It's their main class feature.

[Gildedragon]

Yeah. It seems you can keep trying as FRAs until you catch the fiend.
I do reckon that after the first try you might become the focus of their ire so taking 20 might not be allowed.