Spell Storing reads:
"Anytime the weapon strikes a creature and the creature takes damage from it, the weapon can immediately cast the spell on that creature as a free action if the wielder desires."
I was wondering, if I were to cast Silence into a spell storing weapon, would I be able to use a sunder attack to deal damage to an item to release the stored spell upon it?
RAW: No, as it needs to strike a creature and cause damage to meet the trigger requirements
RAI: Probably Yes, go swing that Pickaxe with Silence.
related topic. the spell storing enhancement must be placed on a melee weapon, but what about dual purpose weapons? does the spell storing effect work on a dagger if it is thrown?
No, because it does not work with ranged weapons and you are not in contact with it at the time of damage to make the trigger decision.