Jon A. writes:
No, the myth that an owner could just willy nilly make up a part on
his own.
I don't expect you can make a prop out of adobe and use it, but other
than silly extremes like that, yes, you can make your own parts.
See:
http://www.geocities.com/CapeCanaveral/Hangar/5511/
towards the bottom of the page.
-jav