The amount of gold on an "Immersion" plated board is only a few microinches think, usually less than 10. When you solder a component to that surface, some or all of the gold (depending on how long the solder stays heated/melted) mixes in with the solder joint. If the percentage of gold in the solder joint is high enough the joint will be brittle, but it won't be that high with such a thin immersion finish. Trying to solder to a thick electroplated gold surface is a different story, however, but you can calculate it yourself by comparing the thickness of gold plating with the amount of solder paste you are applying to the lands in question. I can't remember the exact percentage that means you are getting into the "danger zone", but someone here will know it, or you can search the TechNet archives at: http://listserv.ipc.org/archives/technet.html good luck, Jack --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------