Bill: Also remember there is ELECTROLESS Gold....as well as electrolytic, and immersion....and to answer your question, and another question on the forum in the same message.... ABOUT PLATING...ELECTROLYTIC, ELECTROLESS & IMMERSION... All plating means to convert (in chemical terms "reduce") a metal in solution, also referred to as a metal "ion", to the solid metal. This means transfering electrons to the metal ion in solution...this is true for ALL plating. The difference in the different kinds of plating is the source of the electrons. Electroplating (electrolytic) supplies the electrons from something the industry refers to as a rectifier...which could also be regarded as an "electron pump". In Electroless plating the electrons are supplied by another chemical in solution, in the case of Electroless Nickel, it is Hypophophite, (which, incidentally, is why these deposits also contain some Phosphorus. In Immersion plating, the electrons are supplied by the substrate dissolving, and donating its electrons to the metal being plated....in other words, the Electroless Nickel (a little bit) goes back into solution to cause the (Immersion)Gold to plate. Note, that with electroless plating there is theoretically NO limit on the thickness you can deposit...and in fact, you can get real thick, if you can wait long enough....so, Bill, you can get more than enough Gold using electroless Gold, although you for sure cannot using immersion Gold. In Immersion Plating, as soon as the substrate metal (in the case we are referring to here, it is the Nickel) is covered, plating stops. This is why Immersion Gold never gets beyond 10 microinches thick. And lastly, understand, that there are only some kinds of plating baths for certain metals. There are VERY few metals that, like Gold, can be either electroplated, electroless plated, or immersion plated. Are we all bored with this now? 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 ---------------------------------------------------------------------------------