I swear Vixen is cursed.
First I pulled the mold walls in too closely (top middle). That wasn't going to work, but I thought I could salvage the work by making adjustments in clay, pouring the second side and then repouring a corrected first side (top left). That didn't work. Actually, it would have worked but in doing this I realized that my mold was backward from the start. So I clayed her right-side-up and made the third attempt (top right).
I thought that since she'd already proven to be a troublesome little mare, I would be really sure to give her a good coat of release agent. I'd had some trouble with Imp because I been too sparing with it. I was able to get the resin out from the rubber, but not without snapping his tail. It wasn't a big deal, since the resin would only be used from that point on as a reference when cleaning the castings. I just glued his tail back on and all was well. My fear was that if the resin Vixen became trapped in rubber, what might break would be a leg. And after all that had gone wrong I had no confidence that I would only need her again as a reference! So I gave it all a really good spray.
Apparently too much. A few hours after the pour had set, I went to lift the mold box so I could set it out of the way and Vixen, still nestled in her bed of clay, slipped right out from the bottom. I've never had that happen before! Usually the resin and rubber seal pretty tightly. And in this case the rubber hadn't fully cured. In my experience, if the original comes out really early then the impression in the rubber tends to soften just a bit. And that is exactly what happened. So today I will pour the first rubber piece on her... again. Perhaps the fourth time is the charm!
And it might not be the last, either. I think my problem was an excess of release agent, particularly the amount I sprayed on the interior of the Legos. But if you look at the three rubber pieces, that last one is much darker than the first two. My rubber is now a month old, and those containers have been opened repeatedly, so it has begun to degrade. This next pour should tell me which was the source of my problem.
I cannot complain though. I got really lucky when molding Imp - far luckier than I should have been. If Vixen had been easy, too, I might have gotten too cocky. If there is one rule in ceramics, it is that the medium conspires to make sure that never happens!