You did not say if this was treated water. If not look at the water supply. DI or RO water should not have this problem unless you are running too fast through the wash. Our water here in OK. Has alumn added as a clarifying agent which does show up as white residue -----Original Message----- From: Peter Lee [mailto:[log in to unmask]] Sent: Monday, 15 August 2005 11:20 PM To: [log in to unmask] Subject: [TN] White residues at wave soldering 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------