Chemistry question on aluminum


Hi,
I am not sure if I am getting paranoia about this...

Nowadays, there are many equipment (amps, speakers, etc) that are made from aluminum; from a slab, ingot, extruded and other processes. And I am a sucker for the raw industrial silvery color Aluminum looks. I just dig them. (Think YG acoustics, Audiomachina, Modwright, Jeff Rowland, Acoustic Signature TT, et al)

But I live in the hot and humid tropics. A friend, knowing that I failed Chemistry in school, put a scary thought in me that white powdery substance will form and corrode them in the long run.

Anyone care to give me a Chemistry 101 lesson on this with respect to Audio equipment?

Thanks.
hamburger

Showing 1 response by halcro

There is little chance that any aluminium used in commercial audio products is in its 'raw' state.....ie...unprotected.
At the very least, a chromate coating is the cheapest but anodising is generally the most economically available product and is available in a range of colors and thicknesses (the thicker the coating...say 25 microns...gives added protection).
Powder coating of aluminium is generally cheaper than anodizing these days and is available in hundreds of colours compared to the limited range with adodising.
Powder coating provides greater protection against the corrosion of salt being a paint sealant rather than a chemical deposit as in anodising.
Anodised aluminium WILL be eaten away by salt near a marine environment and even with powder coating......any weakness in joints, edges, drilled fixing holes etc will be attacked thus making any form of aluminium in a marine environment very risky.
Two-pack polyurethane is another protective coating which can be used over aluminium but stainless steel, zinc, copper and even galvanized steel are preferable for coastal environments.
Heat and humidity in themselves will not affect any commercially protected aluminium products.