D ={m}/{V} Kg/M^3 Iron would have higher density than wood given the same volume. So the intermetallics have to be denser for them to sink in the LF solder. Just to clarify. Ramon -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Richard Kraszewski Sent: Friday, July 08, 2005 8:34 AM To: [log in to unmask] Subject: Re: [TN] LF Selective and Wave Soldering None that I am aware of. Fellow Technetters? -----Original Message----- From: Dennis Bang [mailto:[log in to unmask]] Sent: Thursday, July 07, 2005 9:51 PM To: Richard Kraszewski; TechNet E-Mail Forum Subject: RE: [TN] LF Selective and Wave Soldering Hi Richard, Yes I am referring to the intermettallics. Thanks for the clarification. I found an excellent piece in the archives by Kieth Sweatman that answered most of my concerns, but one. http://listserv.ipc.org/scripts/wa.exe?A2=ind0211&L=leadfree&P=R13462&I= -3 Because this intermettallic is less dense than the LF solder it will sink, it remains inside the pot consequently can influence the solder dynamics. Previously this could be removed as part of the dross removal. Is there a way to remove this assuming we failed to manage the Cu content below saturation? Rgds Dennis. -----Original Message----- From: Richard Kraszewski [mailto:[log in to unmask]] Sent: Wednesday, 6 July 2005 10:22 PM To: TechNet E-Mail Forum; Dennis Bang Subject: RE: [TN] LF Selective and Wave Soldering Regarding the LF dross. I suspect that you are referring to intermetallics rather than dross. The source that told you otherwise is correct. Copper-tin intermetallics will now sink rather than rise to the top. This is due to the lower density of Pb-free alloys. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Dennis Bang Sent: Tuesday, July 05, 2005 9:50 PM To: [log in to unmask] Subject: [TN] LF Selective and Wave Soldering Hi all, Just like to know whether anyone has done Lead Free Selective Soldering. Did you have any issues or difficulties? Secondly on LF dross. I read somewhere that the density of LF dross is greater than SnPb and the LF alloy, it will sink instead of float. However a source who are using LF solders have told me otherwise. Is this a big issue, if an issue? How would you handle this? Regards Dennis Bang ################################################# ***** CONFIDENTIAL ***** We apologise if this message has been sent to you in error. We are committed to protecting the confidential information of our customers, our vendors and GPC Electronics. 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Thank you. ################################################# --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------