Toni It is difficult to believe that your problem is caused by moisture in the bare boards, since you have performed surface mount soldering operations and that raises the temperature of the board above 100C during the soldering. If you clean your boards after surface mount soldering operations, you could be leaving moisture in the plated through holes and this is what is causing the outgassing explosions of solder. I would look at this first. The other source of outgassing would be bare boards with voids in the plated through holes (component and via) which allow outgassing of the laminate during soldering temperatures. Check and see if your boards were bought to a specification such as IPC-RB-276 or IPC-6012. This would require your board supplier to do thermal stress/microsections to assure the quality of the boards prior to shipment. Contact them and ask to see the microsections or do your own through holes which exhibit outgassing. Susan Mansilla Technical Director Robisan Lab ################################################################ 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 web site (http://jefry.ipc.org/forum.htm) for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################