Hi John, I answered the wrong question for you. You were asking Tg and I answered CTE. I guess I am getting old... Yipes! I am getting old. That aside, you are likely not so much interested in the Tg of the polyimide as you are in the adhesive used to bond the copper to the polyimide. (there are so called adhesiveless constructions where the polyimide is the only polymer in the laminate.) The net is that the fundamental wording of my previous answer still holds and you need to know what adhesive is being used. There are a few common choices including: acrylics, epoxies and buytral phenolics along with some polyimides. Thus you will still need more detail from the provider. From my rocker (yes, I got back on ;-) Joe --------------------------------------------------- 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 -----------------------------------------------------