Phil, So the following is of concern: :The thickness of the intermetallic formed by thermal aging had little effect on the peel strength until the intermetallic thickness reached above 25 microns (0.001 inch). Then the lead rich layer appeared to be a major the contributor, it formed large lead crystals the fractured easily along grain boundaries." Is this then a thickness specification not to be exceeded, and how easily under what conditions did the fracture occur? Earl --------------------------------------------------------------------------------- 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 the following message: SET Technet NOMAIL 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 ---------------------------------------------------------------------------------