Pouring the first large side piece

In order to do the next pour, the first of the two big side pieces, I need to box the mold back up again. I didn't get the pour spout flush with the sides, however, and the tight fit of the Lego box caused me some concern. I didn't want to take a chance that the pressure might shift the original ever so slightly.



I decided old fashioned wooden mold boards, and a slightly looser fit, were a safer bet.



Here I have sealed any gaps with plasteline and poured the plaster.



With the plaster cured, I have unclamped the mold boards. On the top is my first large side piece, then the gusset, and then my remaining rubber side (with its plaster backing).

Here is my plaster mold so far, with the rubber original inside. I just have one piece left to pour now.



In the next step the only rubber left in my plaster mold is the original. I'll remove that and replace it in the rubber master (pictured behind the plaster) when I'm finished.