Hi Kevin - a quick FTIR analysis of the blue residue should identify its composition and assist in your "where did this come from" effort. Good Luck. Dave Hillman Rockwell Collins [log in to unmask] Kevin Glidden <[log in to unmask] COM> To Sent by: TechNet [log in to unmask] <[log in to unmask]> cc Subject 12/01/2006 01:20 [TN] Any Chemical Engineers out PM there? Please respond to [log in to unmask] om Just a shot in the dark, but any chemistry majors in here? Here is a new problem that popped up- We bond some heat generating components to a pcb using loctite 384. That is a thermally conductive adhesive. After the bonding is cured, the parts are hand soldered (SMT). We use water soluble (Kester 2331-ZX flux) and 63-37 alloy solder. The PCB finish is ImAg. What resulted was a BRIGHT blue liquid residue. Bright blue like the color of blue cotton candy or blue raspberry candy. It appears to be water soluble (visibly removed with DI water, not sure about ionically) I am thinking this has to be some chemical Rx, so I mixed a little adhesive and flux in a beaker, but no color, even with a little heat. Could it be from chemicals in the PCB finish? We use this same combo of materials very regularly and have never observed this phenomenon before. All materials within shelf life. Per the MSDS for the adhesive: Alumina trihydrate: 60-100% Tetrahyrofurfuryl methacrylate: 10-30% Hydroxyalkyl methacrylate: 5-10% Cumene Hydroperoxide: 1-5% Saccharin: 1-5% Ethylene Glycol: 0.1-1% Per the MSDS for the adhesive activator n-Heptane: 30-60% Aldehyde-amine condensate: 10-30% Isopropyl Alcohol: 10-30% 3-ethyl-2-propylquinoline: 1-5% Per the MSDS for the flux: propan-2-ol: 50-100% glycerol: 10-25% 2,2'-iminodiethanol 2.5-10% dimethylammonium chloride 2.5-10% lactic acid 2.5-10% hydroxyacetic acid <2.5% Thanks in advance Kevin G. --------------------------------------------------- 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 -----------------------------------------------------