Werner I'm curious about your statement item 1 '(1) Ag, the main substitute for Pb, readily leaches in base landfills, and produces toxic bactericides' Silver certainly works as a good bactericide, though I wasn't aware it being associated with the term toxic. It's commonly used in cooling towers and swimming pools as a bactericide where a few ppm's will kill virtually all present bacteria and chlorine or Bromine levels which are the main bactericide can be dropped to the legal minimum of 0.5ppm. In small quantities in the blood it is also beneficial to aid the immune system. The world health foundation do have a maximum ppm level for silver in drinking water, but I'm not aware of any issues where it has been considered toxic, other than perhaps around silver processing plants. As far as I'm aware silver as a bactericide also only kills single cell organisms like bacteria and has no effect on large cellular structures, thus it's good for bacteria but doesn't harm people. I suppose in some areas there must be good single celled organisms as well as bad ones, but no bactericide is discriminatory and are used in much higher strengths through conventional drainage systems and by the volumes they are used potentially much more damaging than silver. I'm on your side regarding the lead ban, just not sure of the integrity of your statement regarding silver. I'm not an expert regarding the use of silver as a bactericide but I have been involved with several companies that use it for such, and have designed electronics for them. Several of these companies had quite eminent bio chemists behind them, who I believe would also be surprised at your comment. Brining this into some possible reality, I'm also surprised enough lead leaches from a general mixed household waste landfill site to form any concentration where it could be considered dangerous. We used it for water pipes for enough years without seeing many problems. Regs Mark Dr. Mark Vaughan Ph'D., B.Eng. M0VAU Managing Director Vaughan Industries Ltd., reg in UK no 2561068 Water Care Technology Ltd, reg in UK no 4129351 Addr Unit3, Sydney House, Blackwater, Truro, Cornwall, TR4 8HH UK. Phone/Fax 44 (0) 1872 561288 RSGB DRM111 (Cornwall) _____ From: tinwhiskers-bounce@xxxxxxxxxxxxx [mailto:tinwhiskers-bounce@xxxxxxxxxxxxx] On Behalf Of Engelmaier@xxxxxxx Sent: 08 June 2008 20:39 To: tinwhiskers@xxxxxxxxxxxxx; salag@xxxxxxxxxxx Subject: [tinwhiskers] Re: ACE Develops Lead Tinning Syste m Hi Bob, Well, we are on the same side on the Pb-ban of RoHS. Just so you get any idea, the second slide of my workshop 'Pb-Free Soldering Processes-Survival, Quality, Reliability' reads as follows: POSITION STATEMENT The Pb-ban under RoHS is damaging to the environment, because: (1) Ag, the main substitute for Pb, readily leaches in base landfills, and produces toxic bactericides; (2) Pb in solder is not an environmental hazard, because it requires an acidic environment to leach in a landfill when landfills are base; (3) Because of the much higher Liquidus temperatures for the substitute SAC solders, significantly more energy is required in production, assembly and moisture bake-out; (4) Because of the reduced yields due to SJ brittle failure, PCB and component damage, more electronic product needs to be scrapped; (5) No solution as yet has been found for the tin whisker problem under the RoHS Pb-ban; (6) The unnecessary costs so far have been estimated at $38,000,000,000 to date and $3,700,000,000 annually. Even IPC-D-279 was written way before RoHS [July 1996]. I had no vote on RoHS either, and I strongly criticized the IPC when they jumped on the bandwagon when they thought it was environmentally responsible, and some of us knew better. Well Sony does not have a well-established reliability history; the exploding batteries nade the headlines because of the fires, however, many more of their laptops are failing because of fractured solder joints. There is a whole cottage industry out there repairing Sony laptops as well as others. If you have pre-RoHS electronics, be very reluctant to replace it with "RoHS compliant"-no guarantees there. The problem with electronics is that it has gotten much more functional, much smaller, much more densely packed-all of which gave the industry a headache even without RoHS. That RoHS-monkeywrench just makes things much worse [just think of the much higher processing temperatures]. Since 1973, the electronics content of cars has gone from zero to about 30% [in value], and in terms of reliability issues from zero to about 80%. I always use the "Emperor's New Clothes" fable as an analog to the RoHS Pb-ban. It was not just the Hubble, but also the Magellan and the Galileo that were/are affected by fractured solder joints. I was consulting with JPL on these issues-what actually happened was that the NASA test requirements [on the actual flight hardware, mind you] was the equivalent of driving a car into a stone wall prior to selling it-they consummed 60% of the solder joint life, on average. The basic design was perfect, but the test requirements were mindless stemming from a total lack of understanding of solder creep-fatigue behavior. You need also keep in mind, solder joints do not give dead opens when they fracture but intermittents during transient loading conditions [change in temperature, reorienting of antennas, etc.]. A little history: January 28, 1986-Challenger shuttle disaster delays launch of Magellan and Galileo spacecraft . Prior to launch from Space Shuttle Atlantis on May 4 and October 16, 1989, for the Magellan and Galileo spacecraft respectively, SJ fractures found in electronics of both, and manually (!) resoldered. April 24, 1990 launch of Hubble Telescope from Discovery. Besides the much vaunted optics problem, the Hubble Telescope , also had electronic failures. December 1993-1st Servicing Mission to Hubble Telescope by Space Shuttle Endeavour. SJ fractures found in electronics returned. Reliability issues can only be tackeled one at a the time-it is the metallurgists [I am a ME] that need to tackle the tin whisker problem, but do not hold your breath. As you pointed out, we had tin whisker problems prior to RoHS, just not as many and as prominent. The industry need to address this issue from the component side, read: JEDEC. However, the component manufacturers have a long history of having a 'throw it over the wall' attitude. Regards, Werner Engelmaier Engelmaier Associates, L.C. Electronic Packaging, Interconnection and Reliability Consulting 7 Jasmine Run Ormond Beach, FL 32174 USA Phone: 386-437-8747, Cell: 386-316-5904 E-mail: Engelmaier@xxxxxxx, Website: www.engelmaier.com ************** Get trade secrets for amazing burgers. Watch "Cooking with Tyler Florence" on AOL Food. (http://food.aol.com/tyler-florence?video=4?&NCID=aolfod00030000000002)