Steve The heat alone should not cause a problem; at AT&T we baked immersion silver boards at this temperature for a variety of reasons. What may be of concern are the gases resulting from activating the bonding adhesive, many of these contain sulfur which may tarnish the silver. I doubt, however, it will cause an assembly problem. Best regards Lee J. Lee Parker, Ph.D. JLP Consultants LLC 804 779 3389 ----- Original Message ----- From: Steve Kelly<mailto:[log in to unmask]> To: [log in to unmask]<mailto:[log in to unmask]> Sent: Monday, December 05, 2005 3:26 PM Subject: [TN] Immersion Silver question Good Afternoon, If we have to thermally bond a stiffener onto a flex circuit which has a thick (IPC- 4553) silver coating will it tarnish. The thermal cycle will be approx. 360-370F for 1-1/2 hours under pressure. Thanks in advance. Steve Kelly Steve Kelly PH: (416) 750-8433 FAX: (416) 750-0016 CELL: (416) 577-8433 --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask]<mailto:[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]<mailto:[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]<mailto:[log in to unmask]>: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives<http://listserv.ipc.org/archives> Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16<http://www.ipc.org/contentpage.asp?Pageid=4.3.16> for additional information, or contact Keach Sasamori at [log in to unmask]<mailto:[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 -----------------------------------------------------