Not that strange a request, as a board manufature we use to mark all boards that we were not allowed to put our logo on, prevented a rejected board who made it? problem. as we etched the board I would put a dot or change a feature such as a pad shape that way it was special to our batch. On some finer boards we actualy could print small enough lines so as not to be viable to the naked eye, and would use a sort of bar code 3-4 lines 3-5 mils long by 1-2 mils wide code this was used on boards such as chip carriers that wer only .150 square so no room for a logo. There is a ink made that you can stamp on with a rubber stamp and it is used in the security market to mark property with a uv ink, dont know the manufature I will search the net and see what I can find. robert tarzwell megadan.com --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------