On 5/21/2014 7:15 PM, True North wrote:
I've been looking at a Site where it's claimed that the natural aluminum produces an oxide to protec it's self but the paint interferes with that process.
Anyway I'll let y'all experts debate that.
I dug out my 2012 Legend boat catalogue and it boasts of. 100" or 2.5mm thick 5052 H34 cold rolled aluminum on both hull and sides.
The nearest Canadian competition (Princecraft Holiday WC) uses H36 aluminum, .090 or 2.3mm on the hull and. 072 or 1.8mm on the sides.

Legend claims their's is stronger because it's both thicker and more flexible.
Princecraft claim their's is stronger because it's a harder metal.
I'll let the resident experts decided who's right...I believed Legend two years ago.


The paint has no affect on the oxidation process.

Freshly poured aluminum or freshly cut/machined aluminum forms a layer
of aluminum oxide about 50 angstroms thick within 15 minutes of being
exposed to air. The oxide development drops off rapidly after that.
Undisturbed and unaffected by environmental conditions it will take
years for any further oxidation to take place. The oxide layer seals
off the reaction to oxygen.

50 angstroms is about 0.00000019685 inches.

The early photoreceptor drums used in copying machines used the known
oxidation rate to determine a constant in the electrostatic discharge
that either held or repelled the toner. A photo sensitive coating on
the drum surface determined where the charge would stay and where it
would dissipate.

Before coating the aluminum drums were diamond turned on a lathe to
allow the oxide growth to begin and end. As mentioned, it only grows
to just about 50 angstroms and then drops off to nothing.