When you come across weapons and armor of unusual metals (mithral, adamantine, etc), has anyone ever ran into the PCs wanting to melt it down and make something else from it instead?
Recently they stumbles a +2 adamantine battle axe and they decided they'd rather try and make something else from it instead. I sort of made it up on the fly, but I ruled the moment they melt it down it's destroyed and loses its enchantment (obviously), but I wasn't sure how much adamantine it'd give them so I ruled it'd equal half the base materials, or 3lbs.
Thoughts, opinions?
Also, what bonuses stack with what? Last session I was throughly confused because one of the PCs ended up with a natural armor bonus, deflection bonus, a dodge bonus, his enhancement bonus, and bracers of armor which are an armor bonus...
I know two identical effects don't stack (you use the better), but aren't there a few bonuses that don't stack with other bonuses?
If the bonuses types are different then they stack. If they are the same then they usually don't stack (there are a couple of exceptions). In no cases do bonuses of different types not stack. That is the general rule anyway. If something explicitly spells it out differently then follow that explicit rule.
There are no rules on melting down a crafted item back to raw materials. Some metals may not survive that process and still be good quality. In all cases crafting something new would likely have to be smaller as some of the material would be lost in the crafting process due to ruined material, parts shaved off the final product, whatever.
The characters would be better served by selling the item and using the money towards what they want. Using the tables in the core book, most anything they want is available within the cost limit of the population center they are at.
There is nothing in the PFRPG that I know of that allows them to do what they want BUT the Artificer from 3.5 could do it.
Also sometimes similar bonus of the same type can stack (Dodge comes to mind), you have to read the feat/ability/spell/[source of bonus] to see if it stacks or not.