# Re: [EVDL] Kopr-Shield



## EVDL List (Jul 27, 2007)

*Re: [EVDL] Kopr-Shield*

Excuse this interjection, I only have 53 years of experience in electronics, 
and I know I don't know everything. But I have done some high power work, 
(Nothing over 10,000,000 watts.) To assemble the copper sheet, FR4, and copper 
bus bars, I would mill the bus bars dead flat on one side, tin it with 
silver solder, buff off the copper sheet and tin it with silver solder too 
assemble them,clamp, and sweat them together. then epoxy sheet to FR4 and after 
epoxy firms up,drill and tap #6 holes thru the FR4 into the bus bar every 1/2 
inch and insert machine screws to make a BULLET-PROOF assembly. 


In a message dated 1/21/2009 5:39:36 P.M. Eastern Standard Time, 
[email protected] writes:

I was thinking about this after I posted, and I figure I can do some 
testing by cutting two 1" x 1" x 1/4" pieces of my bus bar, clamping 
them together, measuring the ohms, then trying again with the Kopr Shield.

It was Otmar that suggested the Kopr-Shield, and his opinion carries a 
lot of weight, but he didn't specify what sort of punishment he was 
subjecting it to.

dave cover wrote:
> Let us know what you find out if you do any testing. I'd like to find
> something better than NoAlOx.
>
> Dave Cover
>
>


> Eric Poulsen <[email protected]> wrote:
> >
> >
> >> In a similar vein, I'm bolting copper bus bars to copper plate that has
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] Kopr-Shield*

What you describe is the plan for permanent construction. This is 
supposed to be a modular test-bed, meaning the power modules (6 switches 
+ 6 diodes) can be added or swapped out. The only difference is not 
soldering, so that it can be more easily de-constructed. I'd rather it 
didn't de-construct itself, so I want to keep things cool and conductive.

[email protected] wrote:
> Excuse this interjection, I only have 53 years of experience in electronics, 
> and I know I don't know everything. But I have done some high power work, 
> (Nothing over 10,000,000 watts.) To assemble the copper sheet, FR4, and copper 
> bus bars, I would mill the bus bars dead flat on one side, tin it with 
> silver solder, buff off the copper sheet and tin it with silver solder too 
> assemble them,clamp, and sweat them together. then epoxy sheet to FR4 and after 
> epoxy firms up,drill and tap #6 holes thru the FR4 into the bus bar every 1/2 
> inch and insert machine screws to make a BULLET-PROOF assembly. 
> 
> 
> In a message dated 1/21/2009 5:39:36 P.M. Eastern Standard Time, 
> [email protected] writes:
>
> I was thinking about this after I posted, and I figure I can do some 
> testing by cutting two 1" x 1" x 1/4" pieces of my bus bar, clamping 
> them together, measuring the ohms, then trying again with the Kopr Shield.
>
> It was Otmar that suggested the Kopr-Shield, and his opinion carries a 
> lot of weight, but he didn't specify what sort of punishment he was 
> subjecting it to.
>
> dave cover wrote:
> 
>> Let us know what you find out if you do any testing. I'd like to find
>> something better than NoAlOx.
>>
>> Dave Cover
>>
>>


> Eric Poulsen <[email protected]> wrote:
> >>
> >>
> >>
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] Kopr-Shield*

None of the pastes or greasy mixtures with copper and / or aluminum granules 
mixed in are conductive, their purpose is to prevent corrosion not 
conductivity, because all oxides and corrosion is non-conductive, it is the metal to 
metal contact held by the bolts which will provide the conduction in your 
assembly. The Kopr-shield will only prevent the junction from oxidizing it does 
not add to conductivity itself. Yes I have used it, and in cool (under 100 
Deg. F. ) situations, Vaseline was just as effective, on pc boards conformal 
coating protects conductive traces from corrosion. There is a silicone grease 
called "Heat sink compound" which increases conduction of HEAT, but not 
electrical current. (Hope this helps) Dennis @ EVtrainingCenter.


In a message dated 1/21/2009 8:53:34 P.M. Eastern Standard Time, 
[email protected] writes:

What you describe is the plan for permanent construction. This is 
supposed to be a modular test-bed, meaning the power modules (6 switches 
+ 6 diodes) can be added or swapped out. The only difference is not 
soldering, so that it can be more easily de-constructed. I'd rather it 
didn't de-construct itself, so I want to keep things cool and conductive.

[email protected] wrote:
> Excuse this interjection, I only have 53 years of experience in 
electronics, 
> and I know I don't know everything. But I have done some high power 
work, 
> (Nothing over 10,000,000 watts.) To assemble the copper sheet, FR4, and 
copper 
> bus bars, I would mill the bus bars dead flat on one side, tin it with 
> silver solder, buff off the copper sheet and tin it with silver solder too 

> assemble them,clamp, and sweat them together. then epoxy sheet to FR4 and 
after 
> epoxy firms up,drill and tap #6 holes thru the FR4 into the bus bar every 
1/2 
> inch and insert machine screws to make a BULLET-PROOF assembly. 
> 
> 
> In a message dated 1/21/2009 5:39:36 P.M. Eastern Standard Time, 
> [email protected] writes:
>
> I was thinking about this after I posted, and I figure I can do some 
> testing by cutting two 1" x 1" x 1/4" pieces of my bus bar, clamping 
> them together, measuring the ohms, then trying again with the Kopr Shield.
>
> It was Otmar that suggested the Kopr-Shield, and his opinion carries a 
> lot of weight, but he didn't specify what sort of punishment he was 
> subjecting it to.
>
> dave cover wrote:
> 
>> Let us know what you find out if you do any testing. I'd like to find
>> something better than NoAlOx.
>>
>> Dave Cover
>>
>>


> Eric Poulsen <[email protected]> wrote:
> >>
> >>
> >>
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] Kopr-Shield*

I don't know about kopr shield but we've used conducto-lube and
similar silver filled greases to improve pressure contacts. It works
quite well. It is conductive and fills the microscopic voids between
the metal sufaces to increase conduction.




> Eric Poulsen <[email protected]> wrote:
> > I was thinking about this after I posted, and I figure I can do some
> > testing by cutting two 1" x 1" x 1/4" pieces of my bus bar, clamping
> > them together, measuring the ohms, then trying again with the Kopr Shield.
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] Kopr-Shield*

Kopr-shield is also conductive - I haven't used it much, but a former 
employee of mine recommended it highly.

Joseph H. Strubhar

Web: www.gremcoinc.com

E-mail: [email protected]

----- Original Message ----- 
From: "Peter Gabrielsson" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Wednesday, January 21, 2009 9:51 PM
Subject: Re: [EVDL] Kopr-Shield


> I don't know about kopr shield but we've used conducto-lube and
> similar silver filled greases to improve pressure contacts. It works
> quite well. It is conductive and fills the microscopic voids between
> the metal sufaces to increase conduction.
>
>
>


> Eric Poulsen <[email protected]> wrote:
> >> I was thinking about this after I posted, and I figure I can do some
> >> testing by cutting two 1" x 1" x 1/4" pieces of my bus bar, clamping
> >> them together, measuring the ohms, then trying again with the Kopr
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] Kopr-Shield*

To take this a step further, Kopr-shield is a grease that has a fair amount
of microscopic copper particles added in. If you insert your meter probes
into a glob of it you'll find that it has a lot of resistance. How much
resistance depends on film thickness. Apparently the copper particles are
not in intimate enough contact to create a low resistance current path. For
this reason I don't recommended it as an interface between connectors and
cables in a system where you desire minimum resistance, such as the HV
circuits in an EV. If you do choose to use it within a connection, use a
VERY small amount and squeeze the heck out of it!

Ok then, what about the corrosion protection that we want for those
connections? The tried and true method for creating good connections is to
clean the parts of any oxides before connection, then, after mechanically
fastening the clean bare pieces together (hex crimping, bolting, etc.),
shield the OUTSIDE of the connection.
This can be done with sealant lined shrink-tube in the case of cable/lugs,
or by smearing something such as Vaseline over the outside of the mated
pieces in the case of fastened together surfaces. 
Save the Kopr-Shield for lower voltage/lower amperage connections.

Richard Rau
Northwest Electric Vehicles


----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of joe
Sent: Thursday, January 22, 2009 6:18 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Kopr-Shield

Kopr-shield is also conductive - I haven't used it much, but a former 
employee of mine recommended it highly.

Joseph H. Strubhar
Web: www.gremcoinc.com
E-mail: [email protected]

----- Original Message ----- 
From: "Peter Gabrielsson" <[email protected]>

> I don't know about kopr shield but we've used conducto-lube and
> similar silver filled greases to improve pressure contacts. It works
> quite well. It is conductive and fills the microscopic voids between
> the metal sufaces to increase conduction.
>
>


> Eric Poulsen <[email protected]> wrote:
> >> I was thinking about this after I posted, and I figure I can do some
> >> testing by cutting two 1" x 1" x 1/4" pieces of my bus bar, clamping
> >> them together, measuring the ohms, then trying again with the Kopr
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] Kopr-Shield*

The only way to evaluate if the product improves the connection is to
make a bunch of connections and see if the resistance goes down after
you apply the product. Sticking your multimeter probes in a blob of it
is meaningless since the particles are not compressed together. In my
experience with silver grease you only need a tiny amount smeared on
the mating surfaces.




> Richard Rau <[email protected]> wrote:
> > To take this a step further, Kopr-shield is a grease that has a fair amount
> > of microscopic copper particles added in. If you insert your meter probes
> > into a glob of it you'll find that it has a lot of resistance. How much
> ...


----------

