The first method you mentioned has several advantages but the design is incorrect. I assume that if you are going to use a feed and bleed that you will be using a nitic based system. If this is the case you want the fresh chemistry to go into the first module not the second. The most active chemistry (higher normality, lower SG) will then be stripping the tin or tin lead. Less active chemistry will be removing any excessive tin or intermettallic. Feeding fresh chemistry into the second module will increase your copper attack and shorten your bath life. Nothing kills a nitirc solder stripper like copper over 15g/l. The second method is very good from a cost stand point but of course the productivity is lost because you can't use a feed and bleed system. Typically two parts are more apt to give you a less astethic pleasing copper surafce because the second step is typically ferric chloride based. Regards, Chris McGary Dexter Electronic Materials *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * 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] * ***************************************************************************