Silicones are able to withstand a much higher temperature range than acrylics. You are right in your point that they will retain moisture, so if the temperatures are not too extreme and moisture is the primary problem, then I would recommend acrylic or urethane. Silicones are also preferred in situations where a thick coating build up is called for due to dielectric need. Acrylics tend to micro-crack easily if applied too thick. Jon Moore --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------