Changing Weapon Metallurgic Properites

[Voadam]

Complete Book of Eldritch Might has a spell for it but it seems too powerful to me.

Egyptian Gods by Bastion press has one for turning things to silver temporarily.

 

[AuraSeer]

A silver hammer will crack ribs as good as a steel one.

Only in the real world. Physics in the D&D universe don't work the same way, so it's entirely possible that a silver hammer will be too brittle or too soft or otherwise unsuitable for a weapon of any kind.

Anyway, even if it worked it would be kind of pointless, because it wouldn't penetrate DR. The pure metal doesn't cause particular damage to a werewolf (for instance) if it has not been treated. Note that the SRD entry for damage reduction specifically mentions "alchemical silver," not just "silver" by itself.

This isn't just a fluff interpretation, it's a game balance issue. Special materials are given higher prices to control their availability. If you lower the price of silvered weapons, you're effectively weakening monsters with X/silver DR, which is the same as lowering their CR. This isn't of huge importance unless devils or lycanthropes are the center of your campaign, but before you go changing one rule you should be aware of the ripple effect on other aspects of the game.

 

[Ralts Bloodthorne]

Yes, there is. My partner, Kerrick, wrote a spell called alter weapon material, which is in Arcane Strife. It works for all metal types - cold iron, silver, adamantine, whatever.