Hi Paul: Sometimes an uncured or improperly cured soldermask can cause whitish residue on the sides that are exposed to heat such as wave solder process. Chetan >Date: Fri, 15 Jan 1999 17:04:48 -0400 >Reply-To: "TechNet E-Mail Forum." <[log in to unmask]>, > Paul Wareham <[log in to unmask]> >From: Paul Wareham <[log in to unmask]> >Subject: [TN] White blistering on solder mask. >To: [log in to unmask] > >Getting alot of white blister marks on a batch of boards. All boards = >seem to be from the same date code of board manufacture. The marks seem = >to occur over all areas, not just over copper. There is no residue and = >does not scrape, it looks like it is subsurface. To me, it looks as = >though there is some weakness in the solder mask which was brought out = >under the stress of wave solder. The marks are only on the solder side, = >and only seem to appear after they've been washed. Could a defective = >solder mask have been damaged by heat stress of the wave, then providing = >a home from moisture during the wash process? > >Any ideas? > >Paul Wareham >DynaGen Systems Inc. > ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################