Pete,

1. Are you sure the coating is completely cured??
2. Does this coating also have a secondary curing agent
    for "shadow" areas that UV light can not reach?
3. How high was the humidity during application and testing?
4. Are you coating over contaminated surfaces?
5. Is there complete coverage of edges, back sides, beneath, and points?
6. Is the solder mask completely cured and
     compatible with the coating and coating cure process
    (intense UV can damage certain materials)?

These make good starting places for your answer.
I am sure others will add to this list!

David A. Douthit
Manager
LoCan LLC

Peter Z wrote:

> Hi Everyone,
>
> Having trouble with conformal coating.  Currently using a UV cure silicone
> based spray on a PCB with gold plating.
>
> The problem we are experiencing is after the conformal coating is applied
> and curred (0.002" thick), using simple probes with very little pressure on
> the probes, we obtain conductivity between certain traces.  In other words,
> the conformal coating is not preventing electrical conduction between points.
>
> Specificially, we are having difficulty coating vias and SMT
> resistor/capacitors.
>
> We tried increasing the thickness of the conformal coating sprayed, but no luck.
>
> Does anyone have any ideas?
>
> Thanks,
>
> Pete
>
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