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Kelly,

I must challenge your statement:

> "be applied satisfactorily over the
> leavings of low residue flux, or any other residue, could only be
considered
> valid if the conformal coating had been retested and passed the
> qualification requirements of IPC-CC-830, MIL-I-46058, or whatever
> specification"

This is misleading as it implies that any coating so tested is OK to apply
over no-clean. NOT SO! These specifications require testing of the material
on its own, in isolation on coupons that have been cleaned until they
squeak - there shall be no flux present!

In order to successfully coat over no-clean - and it can be done - you MUST
test the entire process with totally representative coupons of YOUR process.

Consider that a conformal coating is a permanent product to do a permanent
job and seals in as well as out and bingo - if you have something nasty
underneath, then it matters not one jot the specification approvals the
coating may have.

I repeat, it can be done, but I did not say it was easy or straightforward.

Regards :-)
Graham Naisbitt