I agree with Brian's assessment. It appears in the pictures that the white mongue does not appear on the solder joints, only on the solder mask in this case. Therefore I am led to believe that it is some type of a reaction with the solder mask. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Brian Ellis Sent: Tuesday, August 16, 2005 2:43 AM To: [log in to unmask] Subject: Re: [TN] White residues at wave soldering Impossible to say without a full rundown of all your materials and processes. However, if this happens with only one flux, I would suggest you start looking at an incompatibility between some component in the flux and the solder mask. What you ***may*** be seeing is the surface of the mask being very slightly attacked, exposing fillers which would normally be invisible. Brian Peter Lee wrote: > Technet, > > I have a question on white residues formation at wave soldering. We > have recently run experiments to test the performance of various > halide-free water soluble fluxes (ORH0 under JSTD-004). The flux was > applied through a spray fluxer and all PCAs were immediately washed > after wave soldering in in-line cleaner, with DI water only. > > Surprisingly, we've identified several PCAs built with flux A from one > vendor exhibiting white residues at various T/H leads on the boards. > See images below. > > http://members.shaw.ca/ppwlee1/Images/White_residues1.JPG > http://members.shaw.ca/ppwlee1/Images/White_residues2.JPG > > What could be the cause and forming mechanism of the residues? What > causes it to become (sometimes) insoluble in water? In general what > approach can be taken to minimize or prevent formation of white residues? > > > Rgds, > Peter > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 1.8e To > unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt > or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET > Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the > posts: send e-mail to [log in to unmask]: SET Technet Digest Search the > archives of previous posts at: http://listserv.ipc.org/archives Please > visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 > for additional information, or contact Keach Sasamori at > [log in to unmask] or 847-615-7100 ext.2815 > ----------------------------------------------------- > -- ______________________________________________ Please note new e-mail address [log in to unmask] --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------