[TowerTalk] Loosening Al tubing to Al Tubing

[Jeff DePolo]

> I finally remembered something from my tel-co employment 
> days. The Western Electric installers, when installing high 
> current, copper, buss bars......... would take a greenie 
> scrub pad, and work some No-Alox into the metal. This did two 
> things: It cleaned the oxides off the bar, and left a very 
> thin coat of No-Alox behind. 

That's correct!  NoAlox, Penetrox A, and similiar compounds made for
aluminum-to-aluminium or aluminum-to-copper joints are often mis-applied.
Smearing it on the surface with a finger, via the nozzle on the bottle, or
the electrician's favorite trick - dipping the end of a  conductor into the
bottle - are not correct methods of application.  The compound has to be
"scrubbed" into the surface using an abrasive applicator, such as a fine
stainless-steel brush that won't shed or otherwise pollute the compound, to
remove the surface oxide coating from the aluminum.

The other mistake I see being made frequently by both electricians and tower
crews is the use of NoAlox on connections not involving aluminum.  For bare
copper-to-copper connections, tin electroplated ground lugs attached to a
copper bus bar, arrestors mounted to a copper bus bar or entrance panel,
etc., the compound should have copper particles in suspension, not zinc as
in most compounds designed for aluminum connections.  Some suitable
compounds for copper-to-copper include Penetrox E from Burndy, Kopr-Shield
from T&B, and Harger HJAJC8.

						--- Jeff WN3A


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