salvaging to get weapon upgrades like bow strings

[Mon Keyphink]

in order to salvage an item to get bow strings and what not does the item have to be purple or special. like shocking bow of such and such. and do u have to use expert kit? and what are the chances of it actually working?

[Xak of the Blade]

When you ID and item and it say you have unlocked (whatever) then you use the expert salvage kit on it and (for my bad luck) about 50% of the time you get the Bow string or grip you wanted out of the bow, other times you get wood :/