I have heard many times that in high humidity environments with very small
amounts of condensing humidity, no clean flux can become re-activated. This
paper discusses some options:
https://link.springer.com/article/10.1007/s11664-014-3609-0

In my opinion, reach out to the part manufacturer and see if you can
perform cleaning in a particular way to not risk having issues.

Tom

On Fri, Dec 1, 2017 at 1:05 PM, Robert Kondner <[log in to unmask]>
wrote:

> I would go for wash and bake but I worry that washing will "Wash Crud Into"
> the shielded areas and the rinse will not rinse it out.
>
> Are your concerns about no clean flux in a marine environment really
> justified or is it hog wash from somewhere?
>
> Bob K.
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Graham Collins
> Sent: Friday, December 01, 2017 10:09 AM
> To: [log in to unmask]
> Subject: [TN] board wash / non-washable modules - the dilemma
>
> Hello Technet!
>
> Wondering what other people are doing with this dilemma.
>
> We have had several customers design in pre-built RF modules on their
> boards.  I totally get why, it is a pre-built, FCC approved, easy solution
> -
> the fastest way to get a good Wi-Fi or bluetooth solution.
>
> Where things go off the rails for me are where this is used in a high
> humidity application (e.g. a marine setting).  We strongly prefer to wash
> boards, we can build no-clean if needed but I'd prefer not to for an on the
> water use.  But the part a customer has designed in specifically says not
> to
> wash it (it has an EMI shield, so they are properly concerned with water
> entrapment).
>
> So - would you:
>
>  - build it no-clean?
>  - leave the part off, build and wash as usual, install RF module later
> using no-clean?
>  - wash it (and maybe bake it to dry it out)?
>  - ????
>
> --
> regards,
>
> Graham Collins
> Senior Process Engineer
> Sunsel Systems
> (902) 444-7867
>