[CR]Just what makes some chrome more durable than others?

(Example: Framebuilding:Paint)

From: Tom Sanders <tsan7759142@sbcglobal.net>
To: <classicrendezvous@bikelist.org>
Date: Sun, 1 Jan 2006 16:15:08 -0500
Thread-Index: AcYPGHFcOEz1W11wR9encsrLg7DRWQ==
Subject: [CR]Just what makes some chrome more durable than others?

Is it thickness of the chrome plate itself? Some variation in the composition of it? Surface or surface preparation beneath it? I mean, leaving aside the storage conditions in which it has been kept, just why is some old chrome just fine and some pretty well shot?
Tom Sanders
Lansing, Mi