In a message dated 5/26/99 8:33:51 AM US Eastern Standard Time,
[log in to unmask] writes:

<< Has anyone ever come across white residues that looks like snow cap
 covering the solder joints? The phenomenon only manifested  a few days
 after Aqueous wash and EDX captured high lead and oxygen. The white
 residues are so stubborn that they could not be dissolved in DI water and
 IPA. We use a water soluble paste and clean our assembly twice
  >>
I have battled this exact problem with a water soluble paste.  I my case it
turned out that the water temperature of my wash was TOO HIGH (believe it or
not) and it caused some kind of separation in the flux residues.  Part of the
residue washed away and the rest stayed there as a virtually non-removable
white residue.  I tried many different solvents, but none worked.  Keeping
the water temperature at about 120F was the fix.  What is the paste you are
using?

Jon Moore
Z-Tech Services

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet 
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################