Mr. Stewart: It is early, and I am just waking up as I type this, and thought I would use your question as a trigger to discuss the no-accelerator type electroless Copper plating system. Incidently, everyone that I know using it loves it, and says their results are better than using an accelerator, and with good reason, it is chemically, a better system. The no-accelerator concept is Shipley "borrowing" a concept that was actually invented by IBM. The "best" catalyst is one that deposits the most Paladium, and removes the most Tin. The normal Fluoboric Acid based accelerators remove both. IBM did some experiments back in the days when they actually made boards, and purely by accident discovered that the best possible accelerator was dilute (5%) warm (100 F) caustic soda. The funny part of that is they did not have a clue why it worked so well, other than it left all the Paladium, and removed most of the Tin. (I talked to the guy presenting the paper about this project, and wound up explaining the chemistry of his own invention to him!) The reason why it worked so well is that the Tin left on the board is in the Stannic state, which is soluble only in dilute caustic, and in HF (Fluoboric decomposes slightly, releasing trace amounts of HF). So the caustic accelerator dissolves the Stannic Tin, and leaves the Palladium behind. Shipley saw this concept, and simply took it one step farther, since the electroless Copper bath contains Caustic, and eliminated the accelerator. Sure Tin builds in the bath, but with bail outs, etc, it never gets too high. Good system, wish I were selling it. The really funny part of this discussion is that since I do not have any commercial interest in the product, such a discussion is okay. If I were selling it, a discussion like this would be "Ganz Verboten".... Rules can never meet the actual needs of real life. Rudy Sedlak RD Chemical Company ############################################################## 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 ##############################################################