Jack you ask a very broad question. I shall use my stock answer of "It Depends". Conformal coating can be applied prior to conformal coating, but you have to ask why. Usually your potting material provides your environmental protection. Conformal coating is then non-value added. If it is there to protect your assembly from the potting material, you probably have the wrong potting material chosen. Are there constituents in potting compounds that can affect components? Sure. There are lots of compounds out there. Choose wisely. Are there residues that can inhibit potting cure? Absolutely. Clean carefully. Test thoroughly. Choose wisely. I feel like the Knight in Indiana Jones and the Last Crusade.... Doug Pauls Jack Olson <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 06/29/2011 10:39 AM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to Jack Olson <[log in to unmask]> To <[log in to unmask]> cc Subject [TN] Potting over Conformal Coat? Are any of you familiar with conformal coating assemblies before applying potting compound? Are there potting compounds that contain harsh chemicals that could affect components? or Are there residues on boards that can affect the curing properties of potting compounds? I can only find one vague sentence about this in the Working Draft of IPC-HDBK-850 (3.12.9.1 Compatibility) thanks, Jack ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 16.0 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 For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 16.0 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 For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------