Dear Net, 1. Is there a name, we use smut, for the slimy, dark brown-black deposit in low current density areas on panels in acid copper plating? It wipes off as a goo down to the foil copper. 2. Is it related to DML boards only? Palladium on surface issue? Or is it related to DML's reaction with the brightner system in the plating bath? I've been told it's brightner related, but it never occurs on anything not DML'd. -Cold panels 70 F almost always manifest it. - But recently we saw it on 74 F panels plated at 35 asf for the first 5 minutes. a. bath had been inactive for 5 days, but continuously filtered, and air agitation had been on for 2 hours prior to plate. Anode film? b. design was a horrendous mismatch of copper area. We panelized best we could front side- 1-9" 9-18" the front 1-9" area smutted. Other area were ok. 10x 1x copper area back side- 1-9" 9-18" 1x 10x Any experience with this? We thought we'd shelved this prob. with 98 F rinses in the pre plate. Sulfuric dip and plating bath are at the mercy of ambient conditions, typic 74 F. Thanks, Julie ############################################################## TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################