Most melee weapons and a fair number of piercing projectile weapons can be silvered in order to effect creatures that are not harmed by non-magical or otherwise unsilvered weapons. However there are several factors that your character should take into consideration when having a weapon silvered.
Cost: Generally it costs around 100 gold to have a weapon properly silvered by a skilled weapon-smith. The very act of fusing the metals together can only be done correctly by a trained craftsman. Cutting corners such as simply dipping your sword in molten silver won’t work and will more than likely damage the weapon in such a way that it will ether break when used or become worthless in some other way. The cost involved generally covers the price of the silver required as well as the labor. Roughly 20 arrows can be silvered for the same price as a long sword however the price and quality will very.
Effect: Many creatures including lycanthropes, devils, demons and some undead are resistant to non-magical weapons unless those weapons are silvered. Attacking a wererat for example with a common sword will only do temporary damage and the wound will heal by the following round unless the weapon has been silvered or is considered magical. It should also be noted that silvering a weapon does not effect it’s original damage. For all intensive purposes the weapon functions entirely the same as it’s non-silvered counterpart but will now do damage to creatures in the above mentioned categories.
Production As stated above silvering a weapon is a very delicate process that should only be attempted by a skilled artisan who knows how to blend the metals correctly. Less reputable merchants might simply apply a silver plating to a blade of a low quality weapon and try to pass it off as a “silvered” weapon. While for a short time these will function as a silvered weapon however over time the silver plating will wear off due to repeated use or even sharpening leaving it’s owner with relatively worthless weapon.
Proper silvering takes several hours to complete and is a processes by which the smith slowly heats the metal and then works fine threads of silver into the blade by way of pressing and then hammering causing the blade to take on a silver veined look.
Purchasing: Depending on the skill of the smith in question and the availability of good quality silver a properly silvered blade could quite possibly be purchased anywhere. In areas where were-creatures are a common threat it’s possible that every weapon made is a silvered weapon. In some regions of the world where the danger of lycanthrope attacks are a common problem even tools and farming equipment might be silvered in the event they are the only weapon that is on hand at the time.
Magical Weapons:Unless the weapon was originally crafted using silver or became magical after being silvered is is not only unnecessary to silver a magical weapon but not recommend at all. Tampering with a magical weapon in such a way can have several very unfavorable effects. First and least dangerous being that it renders the magic of the weapon useless and effectively makes it an ordinary weapon once again. Worse yet that it alters the magic in some way making it unpredictable or even a danger to it’s owner and lastly it could cause the weapon to possibly explode violently while being silvered. As a general rule only common “non-magical” weapons should ever be silvered. If you aren’t sure if the weapon is magical you should have it identified by a wizard or some other student of the arcane.