For the same reason we do not chrome anything. We use solid stock aluminum and polish it to a mirror shine, or we annodize it. Even polished aluminum requires a little maintenance to keep up, so if you do not want the hassle, then go with annodized aluminum.
Chromed aluminum is always a problem unless it is done right.. What happens is gases are still being released from the aluminum, and it breaks the chrome layer to get out. The only way chrome on aluminum can be done right is "Show Chrome"; this process requires the aluminum to be dipped at least 3 times; very expensive.
Ken Land
Bullet Lines / Krypt Towers
www.bulletlines.com