Steve - There is an IPC standard test pattern, I want to say B25 or B27, that has interlocking finger patterns which is excellent for the experiment you want to set up. We have used this pattern on occasion to show growth of dendrites in contaminants and to show how they can also be grown thru ultra thin conformal coatings (excluding Parylene). The board can be powered with something as low as 5mv, in terms of a power supply or by a small battery. Bridge a spot with a tiny drop of water and observe under a 30x scope and good light. Once you get the feel of it, then you can set up contamination zones and show the real material effects. My PX is 256.882.4536 if you need further info. 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 ################################################################