RST Engineering wrote:
Conductivity for a hunk of metal 62 mils thick by quarter inch wide by a
foot long where you measure resistance in the micro-ohms means absolutely
nothing -- copper, brass, or aluminum. On the other hand, corrosion means a
lot -- like steel hardware on aluminum, no matter how good the plating on
the steel.

Jim


"ELIPPSE" wrote in message
oups.com...
Brass has substantially less conductivity than copper. Aluminum has
less conductivity than copper, but has twice the conductivity per pound.

All power substations use aluminum bar conductors. The trick with
aluminum conductors is that you must apply something like NO-OXID or
Vaseline to the conductor, abraid it with steel wool or crocus cloth,
then, leaving the grease in place, fasten the conductors together using
Belleville washers. Aluminum starts to oxidize immediately when
cleaned, so the grease seals the surface from air. The spring washers
apply the 1500 psi contact force that assures very low resistance, and
also allows for the difference in thermal expansion rates between the
steel fasteners and the aluminum. For instance, 1/8" X 1" 6063-T5
aluminum, such as in the Macklinburg-Duncan display at your hardware
store, has the same conductivity as AWG 0-1 OFHC copper but at half the
weight and much less cost. That's how I made my two 8' battery
conductors in my Lancair that go from the battery in the baggage
compartment to the engine. This method was given us by Alcoa in putting
in the ground grid for our radar and computers in the Atlas Guidance
system. Rocket Science!