Ken, The answer to your question is "it depends". Yes, I know you are all shocked at my response. It depends on the flux chemistry. If you look in J-HDBK-001, in the section on fluxes, there is information there provided by Al Schneider of Alpha Metals that there are over 30 dicarboxylic acids which flux manufacturers can use in low residue fluxes. Considering the staggering number of chemical proportions involved, there is no way that you can get an answer. Take your question back to your flux vendor and ask if the bake temperatures you suggest are sufficient to fully activate the flux residues and make them benign. If so, how long a bake. We had a question here as to whether or not liquid flux used in hand soldering (which we are trying to discourage) could be fully activated by some of our baking operations, should the flux spread out too far from the heat of the soldering iron. Alpha was able to answer the question for us, but only for the Alpha flux we were using. Keep in mind that you will get a different results for "dried" flux and "activated flux". Doug Pauls "Bloomquist, Ken" <ken.bloomquist@G To: [log in to unmask] D-AES.COM> cc: Sent by: TechNet Subject: Re: [TN] Flux Contamination Testing <[log in to unmask]> 03/21/2003 08:18 AM Please respond to "TechNet E-Mail Forum."; Please respond to "Bloomquist, Ken" Thanks for the responses, as always the TechNet comes through. I do have a further question on this subject that wasn't really answered. Does an elevated temperature bake, at say 80-90 degrees C in ambient humidity, cause any chemical change in potentially trapped flux that would change it's state to make it conductive/more conductive? Thanks, KennyB --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------