Hi Seth - The folks at Enthone-OMI, DuPont Electronic Materials and Lackwerke/Peters all supply via fill materials of varying thermal conductivities. The advantage of these materials over a solder filled via, is that they do not change when subjected to soldering temperatures. Believe me, a solder filled via which disperses part of its contents under a large quad pack or similar can be a mess to deal with. 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 ################################################################