Unless I wanted the pattern to be permanently mounted on the mold box bottom, I used plain white wood glue.  Also used white glue to hold the box sides on the bottom.  Easy clean up and not effected by the RTV.

Charlie

When making a mold out of two part rubber to use to cast a resin part, I use a styrene made mold box into which I attach the master to the floor of the box. After mixing the two part rubber I pour it in over the master.   I have always used rubber cement to attach a master to the floor of the mold box.   When making a mold this past week I had a master which was the side of a reefer rise into the rubber on one end of the mold.   The rubber cement did not hold this time.  So began thinking there may be a better product to use to attach the master part rather then rubber cement.   I am asking those of you who make molds what adhesive you use, if any, to attach a master to the mold box form if used.

Lester Breuer