Hi Cara! Take a look at Klein Wassink's book (ISBN 0-901150-14-2) , chaper 8.1.3 and the reference papers in that section for information on the cause for blowholes. I can't find my references but I believe Colin Lea did a multi-article spread on the physics of blowholing in Circuit World magazine. Good Luck. Dave Hillman Rockwell Collins [log in to unmask] "Cara.Startek" <[log in to unmask]>@IPC.ORG> on 08/09/2000 01:52:17 PM Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond to "Cara.Startek" <[log in to unmask]> Sent by: TechNet <[log in to unmask]> To: [log in to unmask] cc: Subject: [TN] Blow Holes I'm having a problem with blow holes occurring in a thick board that I'm running on a wave solder machine. As a test I am going to bake the boards for 24hrs to remove moisture from the board and eliminate this as a cause of the problem. Is there any thing else that cold be causing blow holes? Cara Startek Process Engineering http://www.leitch.com ############################################################## 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 ##############################################################