weapon upgrades

I have had this question for a while and havn't been able to find the answer. So here it goes.

How do you get weapon upgrages?
I've gotten the upgrades attacked to a purple weapon and its unidentified. I identify it and it says "you have found hilt of whatever" or something like that. I then try to salvage it with an expert salvage kit, but all it gives me are common materials. Did I do something wrong?
Also, is there any other way to get weapon upgrades? Whats the point of purple colored stuff if its not unidentified?

Any helpful answer will be much appreciated. I've gotten these around 3 times and its never worked. So please help me before I screw up again.

You didn't do anything wrong. The expert kit doesn't guarantee you an upgrade, just a better chance to salvage it.

Really? I have to be the most unlucky person than because i've tried a lot.
Thanks anyways.

That has happened to me a LOT! Seems sometimes pointless to use the expert salvage kit when it so rarely gives you what you are after. It is terribly discouraging. You can always ask other players if they have what you are looking for and buy or trade for it.