you wrote: >People > >I am looking for some assistance in justifying the non-use of silicone >grease, ie Dow Corning 304, near soldered joints. > >Could someone please supply me with a route to suitable >documentation/reports to support this? > Past experience with thermal greases in a military manufacturing environment has demonstrated the following problems: 1. Thermal grease is removed by common solvent or saponifier cleaning systems. Depending on the amount of contamination concentrating in the wash tank, other product cleaned in the same system may have significant amounts of silicone residues. 2. Thermal greases can easily contaminate fingers, gloves, cots, mats, totes, bags and the like. In this case, any surface making contact with the contaminated part will spread the silicone. 3. Small hand clean pans of solvent used in low volume military applications increase the cleaning problem noted in #1 above. The results of these contamination scenarios are: 1. Conformal coating with Type AR or UR materials will dewet contaminated areas. I won't speak for other coating types - no experience. 2. Wave soldering can be affected because the liquid flux dewets from the contamination, and the oxides are not removed and the solder has a harder time wetting. The same could affect solder paste to some degree by providing a physical barrier. Alternatives exist in the form of self-adhesive thermal pads, curing silicone or other thermal adhesive, that are easier to use\apply and DO NOT WASH AWAY. Use that as your lever, thermal grease is not guaranteed to be there when you need it. Steve Mikell SCI Systems Plant 13 ################################################################ 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 ################################################################