Etch conditions for Kovar are pretty much the same as Copper with Ferric Chloride. A lot of the small houses etch Iron based alloys first with Ferric Chloride, then finish up etching Copper. Usually you use 40+ Baume' Ferric Chloride, and the key issue is watching the HCl, you keep it low to give you good "etch ratios", and higher to increase speed. Rudy Sedlak RD Chemical Company --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------