The next logical step in the ballast wagon kit development is to design the main frame.
It's much more complicated than the frame for the DZ I did previously.
For a start it is part open structure, part flat platform. I had to factor in accommodating the ballast door / chute assembly in the centre of the wagon and the bogie mounting points which have to sit down below the rest of the frame, meaning the top surface as you look at the model would have to at the top of the open mould for casting.
To make like easier I used pre-cut styrene strip to the same height as the frame on the sides so they should match up perfectly as the meat in the sandwich, as it were.
Here it is glued to a sheet of styrene which will form the bottom of the mould box.
And here is the first casting produced from the mould. In this picture you get a better view of the thin platforms at each end, which are cast just half a mm thick to save resin.
Once I've made masters for the ends we can glue this to the sides and see if we end up with something that looks like an NG-Y, or not.