Nope, none... Yes, ammonia solution, Geoff, absolutely correct. Not pure NH4. Most acids and bases require a carrier like water to perform their intended function. Chemistry requires it.
Yup on the de-ionized water, as was suggessted in previous posts. In fact, it's probably the most important step in this example (we're talking Windex after all, not high-proof industrial strength caustic solutions), or in general in any case. If one we're using a higher order caustic in a commercial application, I might be inclined to be more adamant about the need for careful neutralization of the solvent, as effluents from the process will inevitably end up in the local environment, but for the numbers I'm guessing that we're talking about, it's probably not having a great impact... (As some of us might recall from 7th grade science, the single most important thing to remember when working with an acid/base that will end up in a drain is that sufficient dilution, ie, mixing it with generous amounts of water, is critical in minimizing the adverse effect it will have when exiting one's lucrative business and subsequently entering the Earth's ecosystem. But I digress...) Merry Christmas, aj >-----Original Message----- >From: [EMAIL PROTECTED] >[mailto:[EMAIL PROTECTED] On Behalf Of Geoff Harland >Sent: Monday, December 18, 2006 8:02 PM >To: Protel EDA Discussion List >Subject: Re: [PEDA] "No-clean" flux leakage, was: (500V power supply) > >...to be pedantic, mixing ammonia with >water results in a mix of NH4+ and OH- ions, and it is the >latter which results in the mix having a pH exceeding 7.0.> >However I fully agree that if anyone was to follow up with a >mildly acid wash, then it would be very prudent to ensure that >the boards did not end up in an acidic state afterwards. It >would probably be prudent to also have a following wash >consisting just of (deionised) water, so that if the >consequence of the previous (mildly acidic) wash was to leave >the board either very mildly acidic or very mildly alkaline >(if the pH of that wash had not been fully "spot on"), then at >least the pH of the board in its very final state would still >be closer to 7.0 than would otherwise be the case. This e-mail transmission and its attachments may contain information from Avtron Manufacturing, Inc. that is proprietary, privileged and/or confidential and is intended exclusively for the person(s) to whom it is addressed. Any use, copying, retention or disclosure by any person other than the intended recipient or the intended recipient's designees is strictly prohibited. If you have received this message in error, please notify the sender immediately by return e-mail and delete all copies. ____________________________________________________________ You are subscribed to the PEDA discussion forum To Post messages: mailto:[email protected] Unsubscribe and Other Options: http://techservinc.com/mailman/listinfo/peda_techservinc.com Browse or Search Old Archives (2001-2004): http://www.mail-archive.com/[email protected] Browse or Search Current Archives (2004-Current): http://www.mail-archive.com/[email protected]
