You try with solid body options for the two part files.. Then hide one solid body ( in your case, Hard plastic first stage), then work with soft plastic., so that both will be present there, but one hidden and free from all operations doing on second body.
Other method is save the file once again, then delete the hard plastic and make it all alone a soft plastic body.
I wasn't really thinking when I modeled the first and second stage shots of a molded part into a single file. So the hard plastic first stage and the soft plastic second stage are all in the same part file. Now the hard plastic first stage is fine but we want to do some experimental soft plastic forms. It would be significantly better to have these as individual parts rather than more features inb the same part.
In Unigraphics they had this slick command where you could select a solid and do a save as and all the features that created that solid would be saved into the new file. Does Solid Works have any similar command or if not what is the best way to separate these two files?
Thanks in advance for the help!