You inclinations are good. It is a real possibility.
When I was working at a lab, we documented failures caused by mixing OA with
rosin type fluxes.

It is possible (though it takes some work) to mix the two with saponified
wash and DI rinse but not DI alone. 

In a case like yours where your supplier is dumping and unknown flux residue
into your system, you have a situation that I could consider unacceptable
for high rel, high risk, high value application. 


****************************************

 New address & phone numbers below

Guy Ramsey

R&D Assembly
1660 East Race Street
Allentown PA 18109-9580
(610) 443-2299
FAX (610) 443-1622

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Kevin Glidden
Sent: Monday, April 09, 2007 9:08 AM
To: [log in to unmask]
Subject: [TN] Cleaning rosin flux with DI water..

Anyone have data as to what can happen if you remove (should actually say
ATTEMPT to remove) rosin flux residues with DI water?
 
Long story short, we buy a transformer that the mfr told me is soldered with
rosin, medium activity flux.  Their cleaning process is  "scrape flux
residues with a knife"....enough said about that...  We solder with organic
high activity and clean with DI water.  Guess what - return from field with
fire on the pcb...burned out a trace through the PCB under the power pin of
the transformer.  Since learning of the above info, I am inclined to think
maybe the rosin residue could have trapped water or OR flux / flux residues
and created a nice little corrosion spot.
 
Anyone have opinions or experience on what can happen if you try to clean
the "no clean" with just water?
 
 

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