As an OEM of radio transceivers, we specify a product called "Omikron Immersion White tin" as a solderability protective coating on our circuit boards. 60-80 microns works well for us in terms of shelf life and the coating does not have the issues of whisker formation associated with commercial gray tin. However,if the board sits around too long at higher temperatures, the CuSn inter-metallic grows in thickness at the expense of the solderable tin rich surface. The chemistry manufacturer has a tech sheet on the time/temp profile. (970-346-8002). Ron VandenDolder Manager, Manufacturing Millitech Corp [log in to unmask] -----Original Message----- From: Neil Atkinson [mailto:[log in to unmask]] Sent: Tuesday, June 08, 1999 3:07 AM To: [log in to unmask] Subject: Re: [TN] Immersion Silver With reference to some of the comments made on immersion silvers (not mentioning any trade names). Our experience with these finishes has been that they 'tarnish' very quickly in open air and although all PCBs should be handled carefully, stored / packaged correctly etc. HASL is certainly much more forgiving than the immersion silvers in our experience. The immersion tins which are currently on the market look much more promising and initial tests we have carried out on Unicrom (manufactured by cimatec have looked hopeful but I would be interested to hear of any other experiences with immersion silvers / tins. Neil Atkinson Quality Manager Stadium Electronic Controls ################################################################ TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################ ################################################################ TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################ ################################################################ TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################