Anti Corrosive Zinc Paste for Electrical Connections                    12/03 Updated 3/07, 12/08 R. Kwas          

To get trouble-free service from electrical connections in our vintage vehicles, is pretty important.  To help with this, I highly recommend the use of Anti Corrosive Zinc Paste (ACZP).  This is paste of conductive Zinc particles in suspension, and should not be confused with insulating dielectric grease, which is often also recommended (maybe because the word dielectric has the word "lectric" in it, so it must be good for 'em...WRONG!), but which is not the right solution.   Why anyone would want to apply an insulating grease on a place where you want a good electrical connection is beyond me, because if it got between the contacts, it would actually be degrading the connection, and there is certainly not Condition B protection taking place...read on...ACZP has two distinct advantages as it acts both microscopically as a sacrificial anode and superficially, creating a Gas-Tight-Joint (GTJ) to protect electrical connections....use it on new connections and when restoring old ones!     

Zinc containing anti-corrosive pastes only protect an existing good electrical connection ...they will NOT improve a poor old connection, so they sure as hell wont improve anything if slathered on the outside of a poor connection.  Disassembly and a good cleaning are required first.  This may be as simple as pulling off a 1/4" spade type terminal, and abrading any oxidation from the spade terminal (squeezing the mating terminal to restore a decent spring action...or better yet, and to be sure, replace the entire connector...apply paste to wire after stripping and before inserting into crimp - OPTIMAL!), applying the paste onto the flat terminal, and reinstalling the connector.  On more permanent connections such as the heavy current battery cable connections of the starter/solenoid, this requires a slightly more involved disassembly, but a cleanup to shiny metal is again required, then application of paste, and reassembly...the forces of the fasteners will displace the paste around the joint...excess can be wiped away.

Formulation viscosities range from Burndy's Penetrox, a thick paste with very firm, almost putty consistency, which is just about guaranteed to stay where it is applied - even overhead or at elevated temperatures, to Ideal's much thinner Noalox which totally separates in the container, needing to be remixed before use...disappointing!...I much prefer the Penetrox...it's consistency does make it very difficult to coax out of the plastic squeeze bottle.  I wound up cutting open the half full bottle and repackaging it to a much easier to use flat tin container.  A toothpick or similar serves as a throw-away pinpoint applicator. 

Note: 

Many different styles of connections are used on cars, some of these can be considered to be of a "high contact pressure design" (1/4" push-on, all bolted) but some of these connections must be considered a "low contact pressure design" (544, 122 and 1800E&ES Euro-Fuses, and especially the 3AG fuses used on the 1800; bayonet lamp sockets).  In the "low contact pressure design" case, displacement of the grease from the current carrying area is not assured because of the low pressure, and certainly not as good as it might be, which can in fact make for a poor path for the electrical current, so this is NOT a good place to use the dielectric grease.  Anti-corrosive paste, is, on the other hand perfectly suitable for ALL electrical connections!  There is no need to think about what kind of connection we are using it on!  That is why I make the following statement.

Suggested uses for electrical anti-corrosive paste:  Just about all automotive electrical connections that one wishes to get long-term, uninterrupted service from...including battery, fuse to holder, lamp to socket, antenna connections...etc.  As a matter of fact, if anyone can come up with an automotive connection where it would not be suitable, I'd love to hear about it!

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Added March 07:  

 
Pic of Ohmmeter probes in a dab of ACZP showing non-conductivity
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ACZP is actually non-conductive!  The conductive zinc particles...more like zinc dust really, are suspended in non-conductive grease, and so are not in contact with each other...no direct conductive path actually exists across a blob of it (see above)...so it’s pretty benign stuff at the low voltages present a vehicle’s electric system, and should not be considered to be making electrical contact or carrying any current...and that’s why lathering it onto a connection without first separating and cleaning will only externally cover the connection and not take full advantage of the chemical magic of the zinc particles...

When in place between and around two contacts which have mechanical pressure pushing them together, the benefits occur at the microscopic level.  Three distinctly different conditions take place.  To understand a appreciate the advantage, an finer inspection of these conditions is presented here:

 
ACZP at work!

 
Detail of ACZP at work!

Condition A, Base Contacts are in Direct Contact.  (Great...that’s the whole point!)...not much more needs to be explained here!  These areas are in fact, the only current carrying areas!  Without them, we’re in the dark!

Condition B, Zinc Particles Bridge between Base Contacts:  As the two contact surfaces touch each other either by sliding under substantial contact force (like the push-on connector shown), or by forcing the surfaces together (ring connector where a nut provides the high compression force, or even bare wire in a crimp), some of the particles are sheared or compressed, bridging the two surfaces.  In this case, the zinc particles, being made of one of the least noble metals due to it’s low station on the nobility chart , (see Galvanic Chart), and most willing to give up reactive ions, then act as zillions of sacrificial anodes which give up their ions and do the corroding on a microscopic scale, while allowing the important base metal contacts to keep their ions and thereby remain undamaged by corrosion. 

Condition C, Non-Bridging Particles in Suspension and Encapsulation:  Since obviously most of the paste will be displaced, actually only a relatively small fraction of the zillions of tiny zinc particles will bridge the two base contacts.  In fact, most will just be in suspension in the paste and will not be in physical contact with either electrical contact.  These particles in the rest of the blob of grease which surrounds the connection don’t carry any current (see above), or give up any ions...as a matter of fact, they don’t do much at all besides take up space, and can be considered to just sort-of be along for the ride (kind-of like Steve G. in high school).  

So the secondary benefit is realized from the encapsulation as the soft paste is displaced to the next easiest place to be...right next to and surrounding the joint.  This encases the joint in a protective coating which excludes moisture laden air in Oregon, or salty ocean air in Miami, or sulfuric acid droplets around the battery just about anywhere, from getting to the connection to do their dirty work and compromise it.  The cycle of new moisture getting to the contact surface promoting new corrosion is broken. A Gas-Tight-Joint has been made.  As noted before, with the creamy low viscosity of Ideal’s NOALOX product, the encapsulation benefit will be compromised as soon as the material runs away...and it will...how would you like it if your toothpaste ran off the brush?  ...I personally would look for a new brand of toothpaste!

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Legal Notices:  The terms Volvo and Bosch are used here for reference only.  I am not affiliated with Volvo…although I do also Roll…or Robert Bosch.  Close cover before striking.  Use your directional indicators….  It’s a car, not a phonebooth!  Your mother wears army boots, blah, blah, blah…  Comments on the information are welcome. 

The contents of this article are Copyright © 2003 and 2008 by R. Kwas.  You are welcome to use this article and its contents for non-commercial purposes.  But if you copy and republish it, whole or in part, without giving credit to the author, or linking back to the Sw-Em site as the source, you’re just a lazy, scum sucking plagiarist!  Go work for the Boston Globe or something!  

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Manufacturer's Information follows (my highlights!, my comment!):

From Burndy's site (http://ecatalog.fciconnect.com/fci/datasheet.asp?PN=P8Ab&FAM=Penetrox&P=127610,127616):

P8A Penetrox Anti-Oxidant:  Petroleum Base with suspended zinc particles

PENETROX oxide-inhibiting compounds produce low initial contact resistance, seal out air and moisture, prevent oxidation or corrosion, exhibit superior weathering characteristics, are usable over wide temperature ranges, and provide a high conductivity "gas-tight" joint. All PENETROX compounds contain homogeneously suspended particles. The particles assist in penetrating thin oxide films, act as electrical "bridges" between conductor strands, aid in gripping conductor, improve electrical conductivity and enhance integrity of the connection. The specially formulated PENETROX compounds are for use with compression and bolted connectors providing an improved service life for both copper and aluminum connections. Additionally, the non toxic compounds are an excellent lubricant for threaded applications reducing galling and seizing.

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From Ideal's site (http://www.idealindustries.com/IDEAL-EZ/prodcat.nsf/Tables/Noalox?OpenDocument ):

Noalox® Anti-Oxidant Compound

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A Good Reference:  Radio amateur K1TTT 's page for more good info on these products including pricing/sources:  http://www.k1ttt.net/technote/antiox.html  ]  

Link to related thread (warm wires!):  http://www.brickboard.com/RWD/volvo/1317588/140-160/fuel_pump_wire_connections.html

 

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Placeholder for Galvanic Chart (until I post one, a good one and useful supporting info can be found here:  http://www.azom.com/details.asp?articleID=1177  )

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