Guenter, I would agree with your statements, I have seen and read about these different solder behaviors... can you comment on the crack initiation process, if stress does not last long on a visco-plastic material... we can talk about this off-line if you would like... Marcelo Harris Corp., FL [log in to unmask] ______________________________ Reply Separator _________________________________ Subject: Re: [TECHNET] Rework cooling rate Author: "TechNet Mail Forum." <[log in to unmask]> at smtp