Suzanne - as part of a long term real time shelf, I have tested quite a few of the white tins out there. In all cases the solderability has easily passed the six months shelf life - in one case the test group is over 700 days on a shelf in my lab with no protection and still soldering. It should be noted that these samples when manufactured did not have any Stannic Oxide present (as measured by SERA)in the deposit, one of the major causes for solderability problems with this type of surface finish, similarly the presence of sulfur from the catalyst breakdown was also not present. So to cut to the chase - you will have no problems with 6 months shelf life for immersion tin (under normal board storage conditions) if the deposit is "clean".If you have stannic oxide present or sulfur then its all over. Regards Gerard O'Brien Photocircuits Corporation -----Original Message----- From: Lupita Roberts [mailto:[log in to unmask]] Sent: Wednesday, March 20, 2002 11:34 AM To: [log in to unmask] Subject: [TN] FW: shelve life of pwb's I am wondering if anyone can help me with the shelve life of raw PWB's. I was experiencing solderability issues and oxidation issues with some boards. I was told by several suppliers that White Tin only has a shelve life of 6 months and they were not warrantied beyond that point. I have been unsuccessful in trying to find data in regards to this issue. Suzanne Foulkes QC Supervisor Inservco Inc. LaGrange, Ohio 44050 [log in to unmask] [log in to unmask] ---------------------------------------------------------------------------- ----- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 1.8d 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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 ---------------------------------------------------------------------------------