I have been avoiding doing a split mold due to me trying to wrap my head around some things. I made a crappy picture in paint to help me explain a bit. I am sure I am over thinking these things and when I do my research about it, I just overlooked or misunderstood something. I am thinking about making a mold of my tank on my chopper. I would have to split the tank down the middle lengthwise due to a reverse curve that would lock the mold otherwise. So when you make the 2 parts you make the divider out of metal or plastic or whatever you use, you then us filleting wax or modeling clay to fill the gap between the part and the split flange. I know that you try to use just enough wax to fill any gaps and all, but no matter how hard you try I feel like this will make a small curvature to the mold. So if you do this for both side that you now have a small upside down v where the 2 halves meet. When making the part and you bolt the 2 halves together, do you fill the gap between the halves with wax and if so how to you make sure it is flat and wont transfer to the part?