Hi Ken- In regards to hand soldering flux residues not being reacted, this material is very conductive and moisture absorbing and needs to be fully activated using a secondary heating operation such as an Airvac work station and/or a cure oven that allows the flux to reach activation temperature. Here's a couple links to other studies we have done dealing with activating flux residues. Here are the links: http://www.residues.com/pdf/ProcessRx-09-04.pdf - this one is one of our recent columns from Circuits Assembly and talks about the impact of flux residues that are not fully activated http://www.residues.com/pdfs/foresite_flux.pdf - this one touches specifically on flux residues and hand soldering operations We have quite a few studies dealing with flux residues, and you can find most of them at http://www.residues.com/resources_case.html Sara Gorcos Foresite, Inc. 1982 S. Elizabeth St. Kokomo, IN 46902 (765)457-8095 www.residues.com -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Ken Patel Sent: Wednesday, October 27, 2004 12:56 PM To: [log in to unmask] Subject: Re: [TN] No Clean Sara, For hand soldering and touch-up operation, flux will not be exposed to higher temperature like that reflow soldering. Will that be an issue and if so how one should resolve it? Is the hand soldering flux made to take care of the ionic contamination? Looks like it's s big issue to many of us. Re, Ken Patel -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Sara Gorcos Sent: Wednesday, October 27, 2004 9:29 AM To: [log in to unmask] Subject: Re: [TN] No Clean Hi Ted & TN Listserv, We have found that by doing general board extractions for ion chromatography analysis limits our understanding of the pockets of contamination that occur around specific components and in comparative areas such as the bottom of the board vs. the top. By combining Ion Chromatography with a new localized extraction technology is giving us a greater understanding of these pockets of contamination. No clean flux processes deposit different levels of flux activator in different areas of the board. Touch-up and repair adds to these areas. We have found more failures due to stray voltage in these areas of thick or heavier fluxes that do not get full heat activation through using a localized extraction approach. Here is a link to an article we recently published in our column for Circuitnet that might give you a better understanding of how to guage cleanliness in a no clean process, and what issues are encountered by contaminants being left on boards. It also outlines some recommended limits for various contaminant types in determining cleanliness http://www.residues.com/pdf/FailureOfACircuit.pdf Sara Gorcos Foresite, Inc. 1982 S. Elizabeth St. Kokomo, IN 46902 (765)457-8095 www.residues.com -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Ted Kong Sent: Monday, October 25, 2004 4:48 PM To: [log in to unmask] Subject: [TN] No Clean Hi All, What is the best method to measure the cleaningness of a board that use no-clean process? Thanks all in advance. Ted Kong __________________________________ Do you Yahoo!? Yahoo! Mail - You care about security. 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