Bill, This is fantastic. My wimpy wooden sword just turned into a light saber. Now into battle. Thanks, Phil -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of [log in to unmask] Sent: Thursday, August 30, 2007 12:08 AM To: [log in to unmask] Subject: Re: [TN] The perils of using Alcohol for cleaning TESTING: MIL-P-28809, developed by the Navy to remove and measure ionics from PWAs, requires the use of 75/25 v/v 2-propanol/deionized water. One of their reports contains a page of photographs of 25/75, 50/50 and 75/25 2-propanol/deionized water after use in trying to dissolve WW rosin. The high level of 2-propanol was needed to dissolve the post-soldering rosin flux matrix, which released the ionics into the water for proper measurement. This test method is still in use today. It can be found in J-STD-001, since MIL-P-28809 has been canceled. * The conclusion drawn here is: Alcohol and water are both needed to run this TEST, since alcohol (2-propanol) won't do it alone. CLEANING: Several examples are instructive: 1. Assemblers used alcohol with a q-tip to clean the spot residues from touch-up operations. This worked since touch-up was usually done with a very mild rosin-based flux. 2. British Aerospace built an alcohol cleaning system for use in house, using a PFC (perfluorocarbon) vapor blanket over the hot alcohol to minimize any flammability problems. However, when users tried to run the system to clean heavily contaminated parts, especially to remove greases, waxes, etc. the alcohol just couldn't carry enough solids to be an effective cleaner. It did work satisfactorily to remove dust and some particulate, along with light oils. 3. Forward Technology commercialized an in-line alcohol cleaning system, after inserting a primary tank of the cyclohexane/alcohol azeotrope (ca. 2 parts cyclohexane plus 1 part alcohol). The azeotrope details are in the IPC Solvent Cleaning Handbook, SC-60A. Such systems- since hot alcohol is used- require explosion- proof wiring & switches, both on the equipment and 4 meters L/W/H around it. In this case, the alcohol is just used for rinsing and drying, while the cyclohexane/alcohol does the cleaning and carries the contaminant loading. *I have a copy of the 1977 Navy report that contains the photograph. Let me know off-line if you would like a copy of it. The underlined documents may be useful in making your case to management that alcohol alone just won't remove the ionics per your in-house/customer requirements. Also, the flux and paste formulations of yesteryear were much easier to remove than today's more complex formulations. Bill Kenyon Global Centre Consulting 3336 Birmingham Drive Fort Collins, CO 80526 Tel: 970.207.9586 Cell: 970.980.6373 email: [log in to unmask] (mailto:[log in to unmask]) ************************************** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------