Genny, It is valid as far as it goes. Better test would be to sacrifice a couple of boards and actually put them through all soldering processes as blanks and then look for lack of wetting. Don't forget that the intermetallic growth is heat dependent so something that may pass one reflow cycle may not work for a double sided assembly. If it is double sided run it through a print/reflow/print/reflow and look for non wetting. John John Burke (408) 515 4992 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Genny Gibbard Sent: Wednesday, June 24, 2009 9:16 AM To: [log in to unmask] Subject: [TN] Immersion Tin solderability eval We have some Immersion Tin boards that are several years old. From everything I have read here or elsewhere, ImmSn is supposed to have a short shelf life. 6 mos to a year. No one wants to scrap the boards without testing them, though. How would you verify whether they are still good? We hand-soldered some pads and actually had no problems which surprised me, considering the age of the boards, but I don't know if that is a valid test. Genny --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 15.0 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 -----------------------------------------------------