Historical specs need to be viewed in their context: different board designs, materials of construction, components, fluxes, cleaners and expectations of performance. It would be possible to argue that a modern semi-aqueous process is effective and efficient enough that delayed cleaning is of no consequence with regard to rosin/resin based materials. (usually type L sometimes M ). Conversely modern cleaning solvent formulations can be very compromised by environmental requirements, so similar can not be said of them. My suggestion there would be to clean as soon as work is below the BP of the solvent in use. It's different on water washables (M and H). These can have activity after soldering and thus may continue to interact with the work. Resulting appearance may not be good and reaction products may not be water washable in the process times you have, but could still be potentially hazardous. Some manufacturers can formulate to allow delays for batching, misplacing and so on but the general best practice rule remains: clean as soon as possible after soldering. Regards Mike Fenner Indium Corporation T: + 44 1908 580 400 M: + 44 7810 526 317 F: + 44 1908 580 411 E: [log in to unmask] W: www.indium.com Pb-free: www.Pb-Free.com --------------------- Indium Corporation Incorporated in New York, USA Registered office: (Not for correspondence) 77-97 Harpur Street, Bedford , UK Registered number: fc16473 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of - bogert Sent: Thursday, July 24, 2008 12:09 AM To: [log in to unmask] Subject: [TN] Max time allowed between soldering and cleaning July 23, 2008 J-STD-001 is silent on how long a time span is acceptable between wave or reflow soldering and post cleaning for instances where cleaning is mandated because organic Type M or H flux was used. I believe the historical soldering specs MIL-STD-2000 and MIl-STD-454 requirement 5 mandated no more than one hour between cleaning and solddering. Is there a technically necessary maximum limit and if so is there data to support it? If there is a technical supported limit why should we mandate it in J-STD-001? --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 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 ----------------------------------------------------- ***This email, its content, and any files transmitted with it, are intended solely for the addressee(s) and may be legally privileged and/or confidential. If you are not the intended recipient, please contact the sender by return and delete the material from any computer. Any review, retransmission, dissemination, or other use of, or taking of any action in reliance upon this information by persons or entities other than the intended recipient is prohibited. Messages sent via this medium may be subjected to delays, non-delivery, and unauthorized alteration. This email has been prepared using information believed by the author to be reliable and accurate, but Indium Corporation makes no warranty as to accuracy or completeness. Indium Corporation does not accept responsibility for changes made to this email after is was sent. Any opinions or recommendations expressed herein are solely those of the author. They may be subject to change without notice.*** --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 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 -----------------------------------------------------