Any comment on Steve's stratification theory? A few years back I had SPC charts at a HASL pot at a PC fab, with analysis every two weeks. Cu content stayed 0.21% to 0.24% over a period of 1+ years, even though all we were doing was skimming stuff off the top. Lou Hart -----Original Message----- From: Stephen R. Gregory [SMTP:[log in to unmask]] Sent: Tuesday, August 14, 2001 10:04 PM To: [log in to unmask] Subject: Re: [TN] Solder analysis results Dave, Surely, not ALL 1700-lbs.? Wooo-doggies! I can only imagine what a task that would be!!! I've read some stuff that if you keep the pot static, and keep it at a stable temperature for a period (what this really is, I don't know...there's varying opinions), the metals will seek their own level (according to the different opinions, the copper will be towards the top), then you scoop out out the top layer, and replenish what you've removed with fresh bars. The question that I have though, how did the pot get so out of balance with copper? I've never had a problem with copper content, even when waving OSP boards...tin levels dropping, yes. But not excessive copper...somebody throw some pennies in the pot? -Steve Gregory- > RJ Klien Wassink suggests [bible p 169] pouring contaminated solder at about > 190°C through a 20 mesh stainless steel stariner to reduce copper content to > 0.25%. > > Dave Fish > << File: ATT00002.htm >> --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------