On 7/11/02 12:41 AM, "[log in to unmask]" <[log in to unmask]> wrote: > DI Water itself is not corrosive, but it is aggressive, if you get the > difference. Having been stripped of all it's ionic content, it's "hungry" > to replace those ions, and will draw them from wherever it can. That's what > makes it so effective at removing ionic contamination from boards. However, > it doesn't discriminate about where it draws ions from, and draws them just > as readily from seals and gaskets if it can. Domestic appliance seals are > not resistant to this sort of attack, and the loss of ionic content from > their composition degrades them to the point where they fall apart and dump > more dirt back onto boards than is ever removed. The machines then leak and > eventually become useless for anything. > > Peter > > > Rudy Sedlak <[log in to unmask]> 10/07/2002 09:08 PM > Sent by: TechNet <[log in to unmask]> > > Please respond to "TechNet E-Mail Forum."; Please respond to RSedlak > > To: [log in to unmask] > cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group) > Subject: Re: [TN] Water soluble batch washers.../deionized water > > > > > > > > > The "hazards" of deionized water are somewhat blown out of proportion. > > Deionized water is not really that corrosive, only marginally more than tap > water... > HOWEVER, deionized water lacks the buffering capacity of tap water. (All > that water hardness serves to buffer the pH nicely) So, if the "stuff" > you are rinsing is corrosive inherently, the deionized water also becomes > corrosive, especially to metals. > > However, most of the aqueous cleaners are pretty mild and non-corrosive, so > rinsing them with deionized water should be safe, even for the common home > dishwasher. > > This is assuming that the ratio of (acidic/corrosive) flux on the parts in > the washer to the amount of alkaline cleaner being used is not so bad that > the wash water becomes acidic...then you have BIG problem. > > The answer is to clean just a few boards, OR use a lot of cleaner to keep > the pH above 9, and preferably higher than that... > > Rudy Sedlak > RD Chemical Company > > > > [This e-mail is confidential and may also be privileged. If you are not the > intended recipient, please delete it and notify us immediately; you should > not copy or use it for any purpose, nor disclose its contents to any other > person. Thank you.] > > ------------------------------------------------------------------------------ > --- > Technet Mail List provided as a free service by IPC using LISTSERV 1.8d > 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/html/forum.htm for additional > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 > ext.5315 > ------------------------------------------------------------------------------ > --- > Techies, As Peter said, De-ionised water is aggressive. It will leach carbon from welds and over time, degrades stainless steel for the same reason - as was discovered by the Nuclear Power industry when they found reactor vessels breaking down.....but that would be somewhat more of a problem than a scrapped dishwasher! -- Regards, Graham Naisbitt [log in to unmask] Concoat introduce Concoat Systems, a new Division following the acquisition of the former Multicore SPCID business. MUST System II Solderability Testing Systems CM Series Cleanliness Testing Systems SoldaPro Thermal Profilers Auto-SIR Reliability Testing Systems Please visit our new web site for more information: www.concoatsystems.com Concoat Limited Alasan House, Albany Park Camberley GU16 7PH UK WEB: www.concoat.co.uk Email: [log in to unmask] Phone: +44 (0)1276 691100 Fax: +44 (0)1276 691227 Mobile: +44 (0)79 6858 2121 --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------