C2 Bulkhead connector: apply dielectric grease or not?

[William F.]

Re: C2 Bulkhead connector: apply dielectric grease or not?

What's an "acid brush"?

[Frank D.]

Re: C2 Bulkhead connector: apply dielectric grease or not? ed xexc sz

A ahort-bristled soft brush with a metal handle.

[Joe R.]

Re: C2 Bulkhead connector: apply dielectric grease or not?

I suspect there will always be two camps on this issue, which is much more controversial than I ever expected. In any case, this person offers some interesting history. I believe the person who wrote the folliwing would be in the camp believing that dielectric grease is OK to use in most places, including the bulkhead connector.

http://www.w8ji.com/dielectric_grease_vs_conductive_grease.htm

Gary

Hi Gary:

The web link you referenced was very informative, along with the posts in this thread. Thanks for bringing up this topic and doing some research on it.

When I replace my forward wiring harness, I now plan to carefully clean the contacts and apply silicone grease to them before re-insertion.

I've always been a bit uncertain about using silicone grease on connectors, but based on the discussion and references in this thread, I'm now comfortable with doing it.

[Terry M.]

Re: C2 Bulkhead connector: apply dielectric grease or not?

There are more kinds of silicone compounds than have thus far been mentioned. This is a can of worms I had hoped would die, but I offer the following in the hopes that it does not stir the pot too much. Be careful of what you use.

https://www.escopro.com/dow-corning/molykotetm/silicone-compounds.html

These are industrial products and I am not sure of their retail availability. I am posting this just so y'all be sure to get the right product. I believe choosing the right product will be a lot more difficult than most might think. A few posters have mentioned products that have worked for them. Those are a safe bet. Other products may be less productive. Be careful.

[Thomas S.]

Re: C2 Bulkhead connector: apply dielectric grease or not?

Duke is correct.

The bulkhead connectors were not designed to be taken apart repeatedly. Electrical connectors are designed for specific uses. Most connectors utilize a metal alloy that have certain spring characteristics to ensure that sufficient force is exerted at the mating surfaces. Over time, the metal will fatigue and there can be a loss of contact force. Unless a connector is designed according, repeatedly disconnecting a mating pair can also affect the mating force.

Most connectors have plating on top of the base metal alloy to reduce corrosion. Tin is used in many cases for cost reasons with gold plating as the choice for higher conductively. Also, gold does not oxidize.

The ideal situation is to have the mating surfaces to make 100% contact with each other which is in practice, is not possible. In fact, the actual contacting surfaces for most electrical is surprisingly very small when compared to the total surface areas.

I have been in the electronic distribution business for over 40-years selling various types of components, including connectors of all types. I would place most types of automotive connections used on these older vehicles at the low end of the spectrum which is not to say they are unreliable. Again, in most cases the connectors were not designed to be taken apart for than a few times, of course with some exceptions.
A few years ago, I had intermittent issues while driving where the engine would simply stop running. The problem was traced back to the bulkhead / fuse block connector. I was told that this was a common problem and that I should clean up of the contacting surfaces, use a dielectric grease on those contacts, and reassemble everything. I used burnishing tool which has a hard “eraser” like material specifically designed for this purpose. If you remove the plating on the contacting surfaces of the connector it will corrode.

Dielectric grease is designed to implead the flow of electricity which makes its use on contacts counter intuitive. At the same time, it provides a degree of moisture resistance which is likely the real reason it is somewhat effective when used. If the dielectric grease were doing its job well, you would not have any conductivity at all between the mating surfaces so at best, the grease is just another way of preventing moisture from getting to the connections. There are also anti-corrosion greases that prevent the electrolysis affect when dissimilar metals meet.
I had not thought of using WD-40 at the time but it makes sense that it would have worked equally well and since it could have been sprayed over the whole connector, it would have been a lot faster.