Hi Susan, While the official title of the TM is 'Thermal Stress' test, a solder float test IS a thermal shock (T-shock) test. In this context it may not be particularly important in practice, however when full assemblies are subjected to thermal (temperature) excursions, there is a hugh difference if you perform T-shock (causing transient warpages of component/PCB stressing the solder joints in tension, which is not a loading mode for real product, and starts at T-ramps of about larger than 30 C/minute) or T-cycles (at T-ramps of less than 20 C/minute, where shear loading of the solder joints is dominant). So, as far as I am concerned, why not call a 'spade' a 'spade.' Werner Engelmaier ############################################################## 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 Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################