In a former life, our internal specs for hi-rel (professional portable 
equipment) were:
- if over solder mask, not more than 1/3 the distance between adjacent 
conductors
- if not over solder mask, not more than 1/10 the distance between 
adjacent conductors
- not more than 3 acceptable FODs per assembly
As we used acrylic CC, we could retouch rejects by the judicious use of 
solvents, either locally or totally, and respray.

Brian

On 19/05/2011 22:03, Douglas Pauls wrote:
> Good afternoon all,
>
> I have an interesting question to pose to the forum.  An internal debate
> presently rages internally, so I thought I would turn to cool rational
> people (sit down Dewey).
>
> When inspecting conformal coating, one of the things that "may" be
> considered a defect is the presence of Foreign Objects and Debris (FOD),
> which "might" require disposition.
>
> 1.  Is there any guidelines you all use to differentiate FOD in coating
> that requires action (e.g. FOD as a defect), vs. FOD that does not
> (cosmetic only)?
> 2.  If you differentiate bad FOD from doesn't-matter FOD, what criteria do
> you use?
>
> In essence, how much FOD is FOD.
>
> Thanks.
>
> Doug Pauls
>
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