|Using Anti-Oxidants To Ensure
Anti-oxidant compounds are
not a new invention or idea in the pursuit of good integrity or longevity
of joint connections that make up telecommunication facilities. But
their use has been popularized and improved in recent years with the advent
of synthetic lubricants with wide temperature capacities and improved lubricity.
Many important connections in radio and television work can be easily compromised
over time by water condensation and vaporous atmospheric chemicals. When
dissimilar metals are used in direct contact the effect can occur faster
and with greater severity, especially outdoors. Examples of common trouble
areas are ground terminal connections, radial system connections, RF connections,
and even the bolted joints between stacked tower sections.
There is nothing inherently
wrong with using dissimilar metals in direct contact. But if the joint
is exposed to air, or if the joint commonly passes a great amount of current
then the oxidation that occurs in the metals will accelerate and eventually
the connection will fail. It may even heat to a point where the metals
melt or burn.
An anti-oxidant performs two critical functions. First, the anti-oxidant compound material
placed in the region between the two metal conductors seals out air and moisture.
The use of synthetic lubricants in the base compound ensures that the material is
not miscible with water or other chemicals and cannot be driven out. The second
function is that modern anti-oxidants are electrically conductive under pressure.
This is accomplished by mixing copper, aluminum, lead, and/or graphite flakes in
the 5-10 micron range into the lubricant vehicle and then applying the compound
to the surfaces to be joined. The addition of metal particles into the mixture also
creates a heavy compound which is more difficult to displace by weatherization.
The application of anti-oxidants
is simple and easy. Both the metal surfaces to be joined should be
cleaned and then either brushed with a wirewheel or emery paper.
The ridges cut into the metals in this process are actually beneficial,
and the scraping also ensures that bare metal is reached before anti-oxidants
are applied. The compound may then be applied by any convenient
means (brush or finger). Work the material around a small amount
and don't be afraid to use the compound in a liberal manner. Remember
that filling the air voids in the contact joint is a critical necessity.
Any extra compound will squirt out the side when the metals are joined
together, and it's easy to scoop up the excess and push it back into the
original container for later use.
The next step is tighten,
tighten, tighten. Make sure the joint connection is plenty tight
and that hardware will not back out in use. A weather covering is
a good idea to help prevent external corrosion and to help keep hardware
'from moving. Washing down the outside of the joint with alcohol
will drive off any excess anti-oxidant compound.
Use different compounds
for different types of jobs. For copper-to-copper or copper-to-steel
joints use a copper-loaded anti-oxidant such as our Model 601 Series.
For aluminum-to-aluminum or aluminum-to-copper use a complex compound such
as our Model 602 Series.
Anti-oxidants have no rated shelf life so they may be stored in virtually any location
or condition. Be sure to stir the mixture before use to assure good mixing suspension
of the metal flakes inside.
Sensible use of these compounds
offer a high degree of reliability and long term satisfaction to users
who want serious results in telecommunications work.