Dear Mr. Herse, My understanding talking last Thursday with John Burke of rohsusa.com is that lead-free SAC solder (SnAgCu) doesn't "wick" as well as lead-bearing solder does. The SAC solder itself has a reduced propensity to whiskering (some say it's good enough, military people say not nearly). The limited wicking properties mean that it may not wick all the way up the leg of a tin-plated component lead to cover (and protect) the entire lead. Any exposed tin plating will eventually develop whiskers. Matte tin plating is markedly less likely to whisker than bright tin, however I regard the combination of SAC solder and matte tin as inadequate for long service-life products. Apparently, so does the E.U. commission responsible for RoHS, because they have granted exemptions to products used for military and high-reliability telecommunications applications -- these applications get to keep using lead, at least for a few years. Best regards, Dr. Howard Johnson, Signal Consulting Inc., tel +1 509-997-0505, howie03@xxxxxxxxxx www.sigcon.com -- High-Speed Digital Design seminars, publications and films -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Conrad M Herse Sent: Friday, April 20, 2007 9:08 AM To: ldieguez@xxxxxxxxxx Cc: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: ROHS This was recently forwarded to me by a colleague. Conrad Herse herse@xxxxxxxxxxxxxxxxxx On 04/20/07 11:01, Leonard Dieguez wrote: > A quick poll / question: Has anyone recently had problems relating to > tin whiskers from the non-leaded solder? > > > Leonard Dieguez > > > > -- Attached file included as plaintext by Ecartis -- -- File: (null).eml From: "Dr. Howard Johnson" <howie03@xxxxxxxxxx> To: <hsdd@xxxxxxxxxxxxx> Subject: [hsdd] High-Speed Digital Design Newsletter - - Rollback the Lead-Free Initiative - Date: Wed, 18 Apr 2007 00:04:26 +0000 Content-Type: Multipart/alternative; boundary="NextPart_Webmail_9m3u9jl4l_13815_1176858777_1" ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu