Hi All Here's the challenge of the century (and maybe beyond). I know I'm almost asking for the recipe to turn used solder into 24K gold, but here goes: We design and build considerable numbers of circuit card assemblies for severe environment service, both military and industrial. In most cases, these are conduction cooled. We are currently using a one part, thixotropic epoxy which has a gap fill capability up to about .050" under extreme conditions. It also has an appropriately low CTE and high Tg to minimize its expansion effects on the soldered device. The current material must be dipensed following paste application, but cured after solder reflow. (Its 120 to 150C cure isn't healthy for the paste.) The engineering properties of this current material are outstanding, but it drives a number of producibility problems. I am looking for alternates to this current material which have equal or better properties: Thermal conductivity 7 BTU in/ft2 hr. deg F; TCE of 32 PPM/deg C or lower; Tg 95C or higher and a lap shear value of 800 psi or higher. The material also needs to be process durable to the normal fluxes (OA and RMA) and to various cleaning systems which include DI water, citric acid and long chain alcohols. And, not the least, obviously the stuff needs to be reworkable, just for those times when things don't quite go right. How 'bout it Tech Netters - ANY SUGGESTIONS (that are fit to print)? Regards - Kelly ################################################################ 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 ################################################################