all the numbers you state MArk are not real, we dont just buy raw material we buy a laminate with epoxy and copper , a more realistic set of numbers for your 350 carbon core laminate is cte 5-8 ppm .008 carbon core 50 percent epoxy 2 * 1/2 oz copper one layer fr4 .005 thick with 1 oz copper circuitry. thermal conductance of .008 350 carbon laminate 50 percent epoxy 1/2 oz copper would be 50-70 w/mc xy and 3-7 z w/mc, these are good numbers so drop the carbon only numbers. bob --------------------------------------------------- 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 -----------------------------------------------------