I made a new core-spool from a piece of a pen.
I found a hollow pen which fitted over the bulk loader-axis, then i cut the pen length so that the loader would close ok with the pen-part fitted over the loader axis.
Then I put my 90 meter source spool onto a empty writable cd-rom box (it fit pretty well onto the axis), so that the film could be un-spooled ok.
Then I cut some wire and created an "U" shape, where I used the vertical parts to gouge the actual size of my finished spool in the dark, the length of the vertical parts of the "U", was measured from the film-loader axis to the film-loader edge.
After that, put the wire trough the pen-core, and bent it into a "U" shape. Placed the 90 meter source spool between my feet, sat on chair in the dark and simply hand-wounded the film onto the pen-core (with the "U" wire attached) until i reached the top of the "U".
The wire's secondary function, was to keep the film from sliding off or being wound crooked.
After winding, I removed the wire and put the new spool with the pen-core in the loader and closed it.
Worked well. =)