Stupid question (+ background)

[Lawson Cox]

I have fitted my avatar (35 pickup) with turn signals, with front signals concealed in the horns. Have bad ground problem on left side. Have scraped and sanded off excess paint between body of horn and the bellow, or trumpet which corrected the problem. On re-assembly is it better to leave those surfaces bare metal to bare metal, or put a thin film of grease or dielectric grease between them for better conductivity? (Old inquiring mind wants to know. LOL )

[V8COOPMAN]

Grease is a good thing! Plus, it should aid in keeping the bare metal from rusting. DD

[Overkill-F1]

I like to coat the bare metal with dielectric grease, but others prefer plain grease. Both will keep out the water and help prevent rust and help with the flow of electric current.
...Terry
ps. V8coopman types faster!

[koates]

Lawson, forget the grease, it is an insulator. Use some black paint and tiny brush to seal where horn/bracket meets the fender to seal out moisture. Regards, Kevin.

[Jim in Wisconsin]

Running a separate ground wire works real well, then all the metal can be painted to prevent rust.
Jim S.

[Lawson Cox]

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Originally Posted by Jim in Wisconsin

Running a separate ground wire works real well, then all the metal can be painted to prevent rust.
Jim S.

I was going to run a separate ground wire, but when I slipped it back together it lite up so brite I knew I had a good ground.

[JSeery]

Here we go again! Dielectric grease will block current flow, that is what dielectric means. Plain grease will not block current flow.

[Lawson Cox]

I reassembled the horn and put a little chassis lube between the base and the trumpet. All is well. NOW, to get the horns to working again. I'm stumped at this point. I hope it is not the horn button itself. Will keep on keeping on till I get that solved as well.

[JSeery]

The horns are activated by providing a ground, so you should be able to work your way back and determine where the problem is. Same old diagram! Grounding anywhere along the Black wire should activate the horns.

[Lawson Cox]

Would that be black and yellow?

[JSeery]

Originally Posted by Lawson Cox

Would that be black and yellow?

Sorry, yep, Black/Yellow to the light switch at the base of the column!

[Ol' Ron]

When hooking up my grounds I like to use srar washers, they BITE into the metal. Then paint them

[Paul Bennett]

Originally Posted by Lawson Cox

...is it better to leave those surfaces bare metal to bare metal, or put a thin film of grease or dielectric grease between them for better conductivity?

Do not never ever put dielectric or other grease BETWEEN electrical surfaces expecting to improve conductivity. Dielectrics are insulators as is grease. Dielectric grease is often used on TOP of electrical joints to keep them safe from liquids and gasses which attack the metal joint.

What you want is clean bare metal against clean bare metal, clamped with good force, (and no split or star washers between the conductive metal surfaces which only serve to decrease surface area.) Cover the joint with a small dab of dielectric grease if you must.

I performed many Air Force MIL-F-14072 tests of various grounding techniques in various environments to verify this but apparently human nature seems to get in the way of science occasionally.

Last thought on those star washers which bite into the metal. They do bite until sufficient force is brought to the screw joint when they become totally flattened and don't bite. They gouge the metal and reduce the area. Star washers are, like split lock washers, a spring device with a smaller amount of spring force than split lock washers. Long run they decrease the conductivity and must be placed, if used, outside the conductive metal pieces.

Sorry about any baloons

[37 Cab]

Wonder why all the modern automakers use star washers then?? Maybe you should call em up and tell them the error of their ways.

[Ol' Ron]

That's good information, never knew that. I may have to re-think star washers. However, they have always worked for me here in Vermont with all this salt and rust, kinda of an easy to fix that light on the trailer when it dozent work.

[rotorwrench]

For the naysayers:
Dielectric grease was developed for several uses. In aviation it is commonly used in magnetos to prevent cross firing over the high tension lead end grommets where they install into the distributor block. It is also used a lot for cannon plug connectors when they are in swamp areas like wheel wells and other external compartments. A bolted terminal forces the grease out of the way at clamp up and keeps the moisture out. In cannon plugs it helps prevent any flash over and keeps the moisture out. The pins used in shell connectors grip very tightly and have no problems making good electrical contact with the dielectric grease in place.

I'm not making this stuff up folks. The use is called out in hundreds of aircraft manufacturer's publications so its use is required. I don't need to tell you that the FAA and other civil aeronautics organizations do this stuff for a good reason. Reliability is backed up by excellent scheduled inspection and maintenance programs to keep the flying public as safe as possible.

I use Dow Corning DC-4 a lot.

[JSeery]

Rotorwrench, not sure you made your point clear. One of the major uses for dielectric grease is for multi-pin connectors because it provides protection while providing protection (electrical insulation) between pins. Another automotive application is sparkplug boots, again providing moisture protection and increasing the electrical insulation of the boot.

Do you uses dielectric grease on grounds to metal surfaces? I understand that if the grounding surfaces are making good contact they will squeeze most of the dielectric grease out of the mating surfaces so it's insulating prosperities are not a major factor. I just don't see the need for it on a ground to something like a frame or body surface and would use normal grease in that application.

[rotorwrench]

We use it on any electrical connect or bond that is external to the cabin (out in the weather). Many of the engines like the old Bell 47s are not even covered by cowling unless its a 47J model. Every terminal or plug connection gets the treatment. It's not like folks fly them in the rain on purpose but every now and then your going to run into some weather and get wet getting to where you have to go. On a ground terminal lug with a fastener torqued to just 15 to 35 inch/pounds there in more than enough pressure on two clean & prepped bonding surfaces to get an adequate electrical connection. DC-4 is just a gel. It doesn't take much of any pressure to squeeze out a gel like that.

[BillM]

Here is the recommended grease for bolted connections, crimped terminals, battery terminals, etc.
Read more about the NO-OX-ID at the link below.
http://www.sanchem.com/electrical-co...lubricant.html

[Paul Bennett]

I use Stabilant 22A which is quite expensive, $50 for small eye drop bottle. But it works.