>> I have not been able to replace either the gasket or safety fuse for my
>> 1965 mirro matic. The substitute parts now made do not fit properly.

Don't give up until you contact the company about it. Go to the
"Contact Us" part of:
http://www.wearever.com/
And look here as well for parts:
http://www.mirroparts.com/
http://www.cookscorner.com/