I have a customer who gets a gold tarnish on copper traces after cupric etch. It is usually worst with higher weight copper, and looks to be related to rinsing. The tarnish is not removed in the strip/rinse /dry process after etch. When the tarnish becomes extreme it effects the coverage of the Cobra-bond. The alkaline cleaner prior to the Cobra-bond does not remove the tarnish. I'm trying the maximize the rinsing as much as possible. I'm also thinking about upping the normality of the cupric (currently .3). They also etch a lot of boards that been put thru Cobra-bond to help with the adhesion of the dryfilm. This is a new process. Would this cause a problem with the cupric? Any thoughts. Thanks in advance. --------------------------------------------------- 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 -----------------------------------------------------