Larry, this is a very complex issue, and probably does not relate to the Baume of the Ferric Chloride your customer is using, but MAY have something to do with the acidity, or more likely to adhesion of the photoresist. SS is perhaps the toughest surface to prepare for photoresist. Why not give me a phone call to discuss this. This is a matter way off the Technet charter, and besides I am a very slow typist. Rudy Sedlak RD Chemical Company 650-962-8004 --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 ---------------------------------------------------------------------------------