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Thread: electrically conductive paste

  1. #1
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    Default electrically conductive paste

    So.. I have this grounding stud on my car. It connects the ground from the battery to the frame. Its a 1/2" threaded rod. The cable has a 1/2" lug on it. What I have is a large steel washer at the bottom of the stack (against the frame), then a copper washer, then the cable lug, a copper washer on top of that then a copper lock washer then a copper nut.

    I was thinking about putting some electrically conductive paste on the threads of the stud to help with conductivity. It may not be needed but its just something to do. I have 5lbs of this copper powder and cant find a use for it LOL

    I have 5lbs of pretty fine copper powder. Im thinking its about 325 mesh, I have to find the paperwork. Its a high density air atomized powder.

    Anyway. Im thinking of mixing up a very small amount with a grease or other carrier to make a paste and wipe it on the post prior to assembly.

    Any ideas on the carrier?? I have a pretty good assortment of greases. Even thought about petroleum jelly. Or even a silicon based sealant. Or heavy gear oil that will flow off and leave the copper particles.

    Im looking for opinions. Yup, open for opinions. That means any suggestions or comments are welcome. Any and all are welcome... JR

  2. #2
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    Perhaps you could mix it with silicone grease or buy a tube of dielectric grease. I haven't thought about mixing copper powder with anything for better contact.

    The petroleum jelly may work. Can you run a resistance reading before and after to see if it helps?
    It's only ink and paper

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  4. #4
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    Default

    Quote Originally Posted by JRouche
    So.. I have this grounding stud on my car. It connects the ground from the battery to the frame. Its a 1/2" threaded rod. The cable has a 1/2" lug on it. What I have is a large steel washer at the bottom of the stack (against the frame), then a copper washer, then the cable lug, a copper washer on top of that then a copper lock washer then a copper nut.

    I was thinking about putting some electrically conductive paste on the threads of the stud to help with conductivity. It may not be needed but its just something to do. I have 5lbs of this copper powder and cant find a use for it LOL
    There's a product on the market that is a copper-based paste for exactly what you are describing. I have a small tin of it. It was pricey. I think it's made by Wurth, but I can't say for sure.

    If I were going to "brew my own", I would not use dielectric paste... that would be going in opposite directions. Instead I would mix your copper powder with anti-seize. Should work well both for conductivity and for corrosion protection.

    Btw, I would not use the steel washer on the bottom. I would use a wire wheel to get the frame bright at the bottom of the stud, wipe on a very thin layer of conductive paste and then place the copper washer right against the frame. Then the cable lug, then a copper washer, then a steel washer, then a steel lock washer, then a steel nut. The copper washers are for both conductivity and deformation. The steel washer protects the copper washer from the steel lock washer. The steel lock washer and steel nut will be more secure than a copper lock washer, and the steel nut will be less likely to round off while tightening.

    Btw, if you're looking to dispose of some of that copper powder, I'll take some off your hands.

  5. #5
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    Personally I doubt it will make a bit of difference whether you use the copper paste or not.
    I think you may be better off using several grounds, (engine, chassis, body, etc.) and sealing these grounds with a good coat of paint or a moisture proof sealer to prevent loss of conductivity through corrosion. I have installed several such additional grounds on one of my vehicles and after seven years I cannot measure any additional resistance or voltage drop with my Fluke multi-meter.
    But if you're bent on using it, it's not going to hurt.
    I'm sure there must be other worthy applications for the copper powder but at the moment I can't think of any.

  6. #6
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    Your best point of conduction is going to be between the lug and the frame, with nearly as much coming from the other side of the lug and through the stud. Leave out the steel washer. I would probably use shoo goo (aka goop) to mix the copper in with, using a high percentage of copper powder, then coat everything and assemble it. Work quickly once you squeeze out the shoo goo, and wipe away all that you can from the join area when it's put together. Every bit that you're able to wipe away is unable to contribute to the conductivity, so once that's done, leave it to cure. Once it's cured, tighten more if it allows, then apply some paint.

  7. #7
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    Quote Originally Posted by SpyGuy
    If I were going to "brew my own", I would not use dielectric paste... that would be going in opposite directions. Instead I would mix your copper powder with anti-seize. Should work well both for conductivity and for corrosion protection.
    I agree with SpyGuy. Mix it with anti-seize compound. I have a couple of cans of that stuff here( Kopr-Shield ) and it says on the can "Conductive anti-seize compound for the electrical industry"

    It looks and spreads just like any other anti-seize compound I have used but is loaded with copper
    Ernie (VE7ERN)

    May the wind be always at your back

  8. #8
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    Spur washers are a goer in my opinion. They dig into what they are physically connected to. Thats what I used on the ground for my car and welder.

    Same same thing as
    steel lock washer
    ?

    Copper paste, cant see why not, probably a bit much for the application.

    Only my opinion.
    From an early age my father taught me to wear welding gloves . "Its not to protect your hands son, its to put out the fire when u set yourself alight".

  9. #9
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    Yes like spyguy stated - stay away from the di-electric grease (so no silicone bases)

    Most other greases are a no-no also due to the fact that their job is to lubricate and this means it will try to keep the parts "away" from each other, in the application of a massive flat surface area like a washer it could prove counter productive.

    You really do need a specific grease and it sounds like dockrat my have found one for you, I also know that when tightening the lugs that hold aluminum wire in panels that there is a very dark paste that is mandatory to apply to all the cable ends before tightening - don't know if its conductive but it is anti-corrosive.

    Personally I would check into that black battery post terminal gunk they sell for auto's,,, high corrosion protection yet I dont think its keeps the parts away from each other like grease, Toss your copper particles into that stuff and and tighten everything down and I bet you have very good conductivity with an automatic seal.

  10. #10
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    IMHO you should ground to the MOTOR first and then jumper from the motor to the frame and all other points that need grounded. Running the ground from the battery to the frame and then frame to motor just adds two junctions to the start circuit that are not desired. To test your ground take a voltage reading from the negative post of the battery to the frame of the starter while starting the motor. If you have no voltage drop then your ground is in good shape. If you have voltage drop then there is resistance in the ground path that MAY need attention. GM had to replace some transmissions in the diesel rigs that had the starting current running through them because ground wire was not adequate to carry the current to the starter.

    lg
    no neat sig line

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