Susan, As to applying thick unfilled (20 mil) acrylic, epoxies, urethanes etc. coatings that may have a high CTE and may become very rigid when subjected to cold temperature, not only do the solder joints crack, so do some of the components . Some of the silicones are more forgiving, but some of them can cause problems also as they shrink/expand differently that the board or components. Encapsulating the board in heavy coatings, in my experience has led to early failure when assemblies are subjected wide thermal changes. Most of the office environment equipment is not harmed by using heavier coatings, but again there is no need to do so unless you live in some of the more humid climes. I have found failures cause by some coatings when a faily benign environment of -30 to + 80'C was used. Phil Hinton . ############################################################## TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################