The common ammoniacal etchants in printed circuit production are similar to the fomula given from Phibrotech. However, all depend on air oxidation of etched copper in solution from the circuit boards. They will not work by immersion. If an immersion ammoniacal etchant is desired, a supplemental oxidizer must be added. These are the "ammoniacal etchants" used to remove the copper from steel parts that are copper plated to pass thru a heat treat oven without oxidizing the surface of the steel. Is spray or immersion ammoniacal needed? Denny Fritz MacDermid, Inc. ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################ ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################