I agree - mostly. There are some types of spray systems where the gun change is needed, and others that can handle a wide range of viscosities without any hardware changes. I have some of both kinds in production here. One of the major hazards to watch out for with 100% solids coatings, particularly silicones, is the atomization. Silicone, when atomized, tends to migrate to all surfaces in the area around the coater - floors, walls, other equipment, etc. That can be a huge problem. It is a great recommendation to make sure that the equipment manufacturer for the spray system has worked with the coatings that you want to use, or at least something very similar, and has had good results. They should be willing to give you a list of names of satisfied customers that you can contact independently to discuss process performance, technical support, etc. The right company will give you very good results. >>> Aric parr <[log in to unmask]> 04/17/98 06:18am >>> I have at previous employers. Changing the nozzle (or gun) is required if the viscosity changes beyond the limits of the nozzle. Some spray systems are incompatable with some of the newer coatings. Moisture sensitive materials should not use systems where moisture laden air contacts the coating before it exits the gun (common on some types of atomization systems). A 33% solids coating requires .006 in of deposit for .002 of coating thickness, while solventless material only needs app. 1 mm of coating. Some nozzles cannot handle the lower flow rate. Also, some suppliers do not totally understand the new coatings, yet. In short, it depends upon the coating and the gun. Aric Parr ------------- Original Text From: C=US/A=INTERNET/DDA=ID/TechNet(a)IPC.ORG, on 4/17/98 7:12 AM: Hi Technetters Can anyone provide information about experiences with new solventless coatings on Selective Coating equipment. Have you been obliged to change application heads or use special dispense pressures? We are trying to help out some customers who are receiving conflicting information and would appreciate any TechNetter input Kindest regards Graham Naisbitt - Concoat Ltd Alasan House Albany Park Camberley, Surrey GU15 2PL UK Tel: +44 (0) 1276 691100 Fax: +44 (0) 1276 691227 E-Mail: [log in to unmask] Regards, Graham Naisbitt Concoat Ltd Alasan House, Albany Park CAMBERLEY GU15 2PL UK Phone: +44 (0)1276 691100 Fax: +44 (0)1276 691227 email: [log in to unmask] ################################################################ 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 the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################ ################################################################ 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 the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################ ################################################################ 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 the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################