I have a 2 layer board where one side is to be a thermally conductive. It is a poured copper plane with its only connection being to the mounting holes where copper straps will be part of how it gets mounted. We call these cold stations. Usually connectors are mounted on both sides of the board. It is basically to move signals from inside a cryo instrument out to the world. We have done these with a HASL finish in the past but know we can get better thermal conduction if we can leave off the tin/lead finish and just have the bare copper. The holes need to be plated, no solder mask or silk screen is applied. My questions: Is there any thing special instructions I should do on the fabrication drawing besides remove the finish, solder mask and silk screen instructions? The finish I want is the copper any special statements to accomplish this? Besides the oxidation problem do any other problems come to mind that I should be concerned with on a board that will have the copper exposed in this manner? Thanks for you input and time! Dee Stover [log in to unmask] Associate Technician Design National Optical Astronomy Observatory 950 N Cherry Ave Tucson, AZ 85719 www.noao.edu --------------------------------------------------- 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 847-509-9700 ext.5315 -----------------------------------------------------