Hello, Regarding your first example, chances are you have you have residual flux on the boards although it depends on who, when and where they were manufactured. I have been doing repair of various types of PCBs for years and am confident without seeing your examples that the residual flux between the leads of your SMTs in nothing to worry about. Your example of where the hand soldering was done is definitely an example of flux residue. When the heat of a soldering tool is applied to the flux, the liquids evaporate and the heavier solids remain on the board and become crystallized or become a very thick and tacky substance. I am sure that the engineers in the TechNet forum could give you a more technical answer, but I hope this helps in the meantime. Have a nice day, David -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Bissonnette, Jean-Francois Sent: Wednesday, March 03, 2004 2:19 PM To: [log in to unmask] Subject: [TN] Flux Identification and Soldering over gold plated pads??? Got two questions here First I would like to know if there is a way to identify flux residues on a soldered assembly. For instance, I have a series of board that have a glass like residues between the lead (SMT) and quite a lot of it. It looks clear, little bit brownish and it breaks like glass if I apply pressure with a dentist pick. Also where hand soldering was done, the brown color is much more obvious. Second. Any of you ever seen a board with gold plated lands instead of tin plated? Well I would not be able to say it it IS gold plated but it sure looks like it and not copper. Any help would be appreciated. Jean-François Bissonnette Vérificateur, Contrôle de la Qualité Électronique Produits et Procédés Vapor Rail Inc. 10655 Henri-Bourassa O. St-Laurent, Qc H4S 1A1 (514) 335-4200 x2021 (514) 335-4231 fax ***** CONFIDENTIALITY NOTE ***** The content contained in this e-mail transmission is legally privileged and confidential information intended only for the use of the individual or entity named herein. If the reader of this transmission is not the intended recipient, you are hereby notified that any dissemination, distribution, or copying of this transmission is strictly prohibited. --------------------------------------------------- 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 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- 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 847-509-9700 ext.5315 -----------------------------------------------------