I had a pattern in a mould that I believed was mechanically locked. Since all was lost, I wanted to remove the pattern and do a thorough postmortem.
To attempt this I made cuts into the flanged portion as pictured below.
The 2mm wide cuts reduced the rigidity of mould slightly, and to my surprise the pattern could be removed!!!
The mould seems to be pretty good, EXCEPT flange damage - the 2mm wide cuts, hacksaw holes, and loss of some gelcoat at hacksaw holes!!
How do you recommend I repair it? It's still extremely rigid and strong, it just has to cope with a vaccuum bag...