All great advice so far. We use ImAg as our primary finish with little issues. We've covered most all of the bases, right down to specifying the packaging requirements both to PCB suppliers and internally. We perform 2-sided reflow and secondary hand soldering of wires, etc with no issues. We do get occasional fingerprints in the finish from PCB handling, and that's an on-going awareness issue. Also, related to this, we have been considering use of the Cortec VPCI-125 plastic wrap: http://www.cortecvci.com/Publications/PDS/VpCI-125.pdf It is a static dissipative film with anti-tarnishing properties, supposedly good for ImAg as well. IPC-4553 only mentions the silver saver paper though. Anyone yet using this wrap with good or bad results? Offline comments are OK. Kevin -----Original Message----- From: Maurice Dore [mailto:[log in to unmask]] Sent: Wednesday, May 27, 2009 3:36 AM To: [log in to unmask] Subject: Re: [TN] Immersion Silver Steve Good place to start is IPC4553 - Silver tarnishes in the presence of sulfur (Ag2S forms on the surface); a. Storage & Handling Handling- Gloves worn by Operators at all stages of production 1. Immersion silver boards should be packaged as soon as possible, to prevent exposure to chlorides and sulfides in the air. 2. Use sulfur free, pH neutral paper to wrap stacks of parts and then plastic wrap. Storage should be in sealed bags or sealed containers to eliminate direct contact with air. 3. Wrapped packages should be stored below 30°C (86°F) and 75% R.H. 4. Do not use desiccant in the packages. Desiccant can contain sulfur compounds. 5. Adhesive tape, adhesive labels, stamps, markers and rubber bands are forbidden on silver boards and the sulfur free paper. They all contain sulfur bearing compounds that will tarnish the silver coating. 6. If the original package is opened and not all of the boards consumed at the EMS/OEM, they should be re-wrapped as soon as possible and returned to a storage condition, preferably not-to-exceed 30°C (86°F) and 75% R.H. b. Shelf Life - Controlled Shelf Life in unopened Vendor packaging - 6 months and 4 weeks resealed Vendor packaging - Floor Life - Double Sided Reflow - 48 hrs max - Floor Life - to complete all solder assembly (i.e. wave solder) - 7 Days maximum Floor Life c. Corrosion Prevention - Pads are non-soldermask defined, reduces risk of any creep corrosion ? Pad to Pad Clearance reduces risk of electrochemical migration ? PCB Supplier to observe ImmAg Thickness ( 0.2 - 0.4µm ) The key is to reduce exposure time to sulfide and chlorides (remember to check both site levels) - I noticed solderability issues after 14 days exposure time that affects our wave soldering process. logistics of moving between manufacturing sites should be ok if controlled as recommended. Rgds Moss Steve Kelly <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 26/05/2009 22:00 Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to Steve Kelly <[log in to unmask]> To [log in to unmask] cc Subject [TN] Immersion Silver Good Afternoon, Any concerns about using immersion silver as a finish. PWB has to take two reflow cycles, 1 re-work cycle and one hand solder after the two reflows. Parts have to be transported from one part of the country to another after the two reflows. Thanks. 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