aha, notice this is TechNet not software hack forum.  in those type  
of forum it is routinely called each other "stupid  
questions"... ;-).  Hardware/software difference ....
jk
On Feb 27, 2020, at 4:40 PM, Stadem, Richard D wrote:

> You sure are welcome, Jeffrey.
> And never, ever, start off a posting on this forum again with an  
> apology for asking a dumb question. There are no dumb questions,  
> and even after 45 years in this business I (and all of us) are just  
> as much of a "newbie" as you are! There is simply too much to learn.
>
> Odin
>
> -----Original Message-----
> From: TechNet <[log in to unmask]> On Behalf Of Jenkins, Jeffrey (US)
> Sent: Thursday, February 27, 2020 3:08 PM
> To: [log in to unmask]
> Subject: Re: [TN] [External] [TN] No-Clean (ROL0) question....
>
> Doug and Richard,
>
> Thank you both very much I do appreciate both of your assistance.   
> Something in the back of my mind (probably from IPC Cleanliness  
> conferences!) said it’s not the best thing to do.  I also went and  
> pulled the IPC-CH-65 Paul had mentioned prior and I look forward to  
> reading it.
>
> Best,
>
> -Jeffrey
>
>
> From: Douglas Pauls <[log in to unmask]>
> Sent: Thursday, February 27, 2020 12:55 PM
> To: TechNet E-Mail Forum <[log in to unmask]>; Jenkins, Jeffrey (US)  
> <[log in to unmask]>
> Subject: Re: [External] [TN] No-Clean (ROL0) question....
>
> CAUTION: Email originated from outside of Cubic.
>
> Jeffrey,
> I will send you a document that I drew up about 12 years ago,  
> together with the late Dr. Bill Kenyon.  It talks about no-clean  
> fluxes and why someone would choose to clean a no-clean flux.  You  
> might find it of benefit.
>
> There are also a number of excellent papers by Dr. Mike Bixenman of  
> Kyzen on the nature of fluxes under QFNs that more addresses what  
> can happen if those low solids residues do not get to the proper  
> temperature.
>
> Douglas Pauls | Principal Materials and Process Engr | Advanced  
> Operations Engineering COLLINS AEROSPACE
> 400 Collins Road NE, MS 108-101, Cedar Rapids, IA  52498  USA
> Tel: +1 319 295 2109 | Mobile: +1 319 431 3773  
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> lins.com> for all Export Compliant Items
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>
> On Thu, Feb 27, 2020 at 2:21 PM Jenkins, Jeffrey (US)  
> <[log in to unmask]<mailto:[log in to unmask]>> wrote:
> Fellow TechNetters,
>
> I apologize if this may seem like a newbie question and if so I  
> apologize.
> I've used OR fluxes and RO fluxes and have always had them removed  
> by the cleaning process as most of the products that I work on have  
> an expected life of 10+ years.  We've typically validated the  
> amount of WOA and Chlorides and set baselines for those.
>
> Someone posed me a question about cleaning no-cleans. Even though  
> in a perfect world a no-clean flux should be 100% inactive after  
> reflow, I'm betting that's never perfectly the case.   So my view  
> and response was that based on the life span and end use  
> environment, my concern would be humidity/moisture mixing with the  
> residual material and in the long term increasing the risk of  
> dendritic growth and other things.  Am I off the mark?
>
> Thanks,
>
> Jeffrey A. Jenkins, CID+
> Principal Engineering Designer
> Cubic Mission Solutions
>
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