The presence of lead in the joint allows for the theoretical possibility of the Sn/Pb/Ag eutectic forming. This has a solidus of 179C [The liquidus of the solder will still be >220C] If this Pb is washing off your boards/components, there is a real possibility of a locally high concentration of Sn/PB and therefore of a depressed Sn content in the adjacent area leaving a surplus of ...it begins to be hard to forecast everything. Whatever there is the distinct possibility of a different strength/composition/flexibility layer in the solder joint. This discontinuity would be visible in micrographic section and is undesirable from a reliability point of view. You may also be seeing effects of this in terms of surface appearance - slight frostiness - although probably joint shape and wetting etc are not [yet] effected. In a perfect world you solder lead free components with your Sn/Ag solder, in a real world you have an analysis program so you can monitor these increases and take corrective action. The only thing which puzzles me is the amount - 1% represents a lot of devices and I would have thought regular drag out and replenishment would not normally allow this build up. Perhaps you have a nearby Sn63 machine? Regards Mike Fenner Applications Engineer, European Operations Indium Corporation T: + 44 1908 580 400 M: + 44 7810 526 317 F: + 44 1908 580 411 E: [log in to unmask] W: www.indium.com Leadfree: www.Pb-Free.com -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Stolar, Paul W Sent: Tuesday, January 14, 2003 9:49 PM To: [log in to unmask] Subject: [TN] Pb Does anyone no what 1% Pb in SnAg solder will do? I just got a solder analysis done for my wave. Paul Stolar Materials Engineer Baker Atlas 713-625-5376 --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------