As a supplier of solder/fluxes and conformal coatings I would just like to second (third, etc.) what some of our esteemed colleagues have said. Testing is critical in these cases. It is certainly possible, we have several customers who build high reliability (automotive, military, etc.) who have qualified material sets. Some of the places to look where there might be hiccups would be if there is rework - insuring that the flux used in that operation is compatible with all the other material systems being used (not only the conformal coating, but also the other flux residues). In addition to possible adhesion problems between certain flux and coating systems, there is also a danger with some conformal coating chemistries have their curing mechanism poisoned by flux residues. We have observed this in the past, it is rare, but it will lead to serious problems. Also, if you do end up cleaning, making sure any saponifer used will clean the flux used and that you completely remove any saponifier residue, and dry the PWB well prior to coating. Basically, it is going to come down to you doing the qualification to insure that you are comfortable with the reliability achieved when using the materials you have chosen in your process. It certainly would be a good idea to talk to your material suppliers (paste, flux, and coating) and make sure that there isn't already some data on those combinations. Even if they say there is no known problems, you still need to test in your process, because process conditions will play a role in the nature of the flux residue. I hope this helps. Brian J. Toleno, Ph.D. Sr. Applications Chemist Loctite Electronics 15051 East Don Julian Rd Industry, CA 91746 Ph: 626-968-6511 x304 Cell: 626-215-0879 ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. http://www.loctite.com/ ********************************************************************** --------------------------------------------------- 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 -----------------------------------------------------