3 Ohms is not healthy silver epoxy joint. I've been using silver filled 
adhesives for 20 years, and can say with certainty that something is wrong 
when you get such a high resistance value. A normal reading is 10 milliOhms 
or even lower. The resistive path consists of thousands and thousands of 
silver flakes in contact with each other, and they make a low  resistance 
network. Are you sure of doing correct measuring? Have you followed the 
curing instructions? Were the sites cleaned before application of the 
adhesive? Enough adhesive dispensed?

Typical volume resistivity is some milliOhms/cm.


----- Original Message ----- 
From: "Eric CHRISTISON" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, July 16, 2009 10:14 AM
Subject: [TN] Silver epoxy - related question


> Interesting thread which prompts me to raise a related question.
>
> I'm using silver epoxy as part of an EMC/ESD shield. It connects a 
> conductive enclosure to a PWB ground plane.
>
> Generally we get a DC resistance across the epoxy joint of about 3 Ohms. 
> However after we subject a device to an ESD spike we find the resistance 
> drops by maybe an Ohm or so.
>
> Anyone got an idea what's happening?
>
> Thanks,
>
>
>
> John Burke wrote:
>> Thanks to all for the replies on silver epoxy - they are as always much
>> appreciated.
>>
>> Best regards
>>
>> John Burke
>> (408) 515 4992
>>
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>
> -- 
> Eric Christison Msc
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