Hello folks,
last week I got an Ultron 1:2/50 Voigtländer with sticky and broken aperture blades that is as old as I am.
So I felt obliged to do everything possible to save it from waste disposal.
After dismantling the lens almost totally I cleaned the aperture blades from denatured fat and rust.
It was impossible to replace the broken aperture blade with a good one, so I managed to remove the broken blade and put all together again.
Now it looks and works fine, and the one missing blade of the 15 aperture blades is hardly noticeable.