"Eisboch" wrote in message
...

"Tim" wrote in message
...



That's a very nice looking craft from what I can tell, but I wonder
what "Marine grade aluminum" is?

Some type of alloy? And I wonder how it would hold up to yearsa of
salt water and electrolysis?


Aluminum is made in many different alloys to achieve certain general
characteristics. I think the RockSalt boats are made of a series 5000
alloy which has desirable attributes such as strength, weldability, and
corrosion resistance, particularly in marine applications.

Aluminum in general is a "self sealing" metal in terms of corrosion
resistance. If you scratch aluminum hard enough to get to the raw metal,
it quickly reacts with oxygen to form aluminum oxide on the surface of the
fresh metal. If I remember correctly, about 50 angstroms will form almost
immediately, then continue to build over time until the metal molecules
are no longer in contact with oxygen and the oxide barrier will stop
growing. BTW, aluminum oxide is non-conductive. That doesn't mean the
boat won't conduct electricity because the oxide layer is relatively thin
(few microns) and will break down at a high enough voltage. Often,
though, low voltage (like 12 volts) connections are difficult to
properly make unless you scrape off the oxide and make the connection
before the oxide rebuilds.

Eisboch


Forgot to include this link regarding aluminum alloys :

http://www.materialsengineer.com/E-Aluminum.htm

Eisboch