These two spells combined make manacles which are impossible to unlock.
Conjure Bands of Iron
Creo Terram 25, R: Touch, D: Moon, T: Individual
Creates a set of interlocked thick iron bands similar in size and style to manacles, although designed to be heavier and with no opening mechanism.
(Base 5, +1 Touch, +3 Moon)
Iron as Viscid Clay
Muto Terram 20, R: Touch, D: Concentration, T: Part
Alters an iron object touched so it may be reshaped like clay while the spell is in effect. Initially desired to reshape iron bands for captured foes, the Magus also found this spell useful to create impromptu tools or devices of iron.
(Base 3, +2 metal, +1 Touch, +1 Concentration, +1 Part)
These spells are part of the free new spells compendium for Ars Magica.