Bright dipping will not give you a protective coating at all. The part will need to be clear anodized for protection after bright dipping (and rinsing, etc.) Regarding rusting - in aluminum we prefer the term oxidizing, the thickness of the anodic film will determine the life - up to 20 years...
Hi Barry:
I worked as an aluminum plate metallurgist years ago. For heavy section - 150mm thick - 7075-T651 plate there are only a few mills that can make it. Alcoa and Pechiney. For thick plate solution treated and stretched, depending on the starting ingot size, there can be center plane...
Here is a simple formula:
L=t/(pi(R^2-r^2))
where:
L = strip length
t = strip thickness (including paint)
R = OD/2
r = ID/2
This formula assumes that the product is tightly wound and the shape is good. It will give you a quick approximation.
Phil
Just a few comments about aluminum (and aluminium!).
1. All aluminum alloys can be work hardened - heat treatable or not.
2. Aluminum does not have a yield strength. Under stress, it starts to deviate from the Hook's law line right from the get go. The "yield strenth" is the 0.2%...