Ditto  to Bob's thought. Localized clean if need be. 

Rich  Kraszewski 
Senior Staff Process Engineer
Plexus Engineering Solutions 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bob Wettermann
Sent: Friday, December 01, 2017 12:28 PM
To: [log in to unmask]
Subject: Re: [TN] board wash / non-washable modules - the dilemma

My vote because this is what we have done for small Proto builds is to leave the module off, build and wash w water soluble flux then install the RF module using the no-clean?

Bob Wettermann
BEST Inc
Your BEST source for PCB Rework/Repair, Training and Tools
847-767-5745


> On Dec 1, 2017, at 10:15 AM, Tom Brendlinger <[log in to unmask]> wrote:
> 
> 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
>>