Werner, I agree with your response to Frank. But have a question; how do you assure that you have good wetting to the base metal surface when good wetting is visually apparent? Are there any subtle aspects of the appearance we should be looking for? Bill Dieffenbacher At 10:56 AM 12/13/96 -0500, you wrote: :Frank, :Please do NOT call silver, or any other surface finish 'highly solderable'. :Surface finishes are NOT soldered to; they certainly promote the flow of :solder across the surface that the surface finishes cover, but the surface :underneath the surface finish need to be solderable and wetted to. These :highly soluble (in tin) surface finishes (gold, silver, sometimes copper) are :very thin and go into solution with tin almost instantaneously. These surface :finishes can be dangerous, because they give the appearance of good wetting :whether or not good wetting has taken place. You can get good coverage this :way without good wetting to the base metal underneath. : :Werner Engelmaier :Engelmaier Associates, Inc. :Electronic Packaging, Interconnection and Reliability Consulting :23 Gunther Street :Mendham, NJ 07945 USA :Phone & Fax: 201-543-2747 :E-mail: [log in to unmask] : : : ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Bill Dieffenbacher Tel. (607)770-2961 Lockheed Martin Control Systems Fax. (607)770-2056 600 Main St. Room R52F email [log in to unmask] Johnson City, NY 13790 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************