I have a left and right mold prepared and to keep the explanation simple think of the molds when together as forming a cavity that looks like an egg. Each mold has a flange all around. The problem is I don’t know how to lay the carbon fibre all the way up past the flange so that after vacuum and cure I have something to trim off to the flange line. It would seem that I can’t lay the cloth over onto the flange as that would cause a small void right at the inside of the flange as the cloth wouldn’t make a sharp 90 degree fold. I have seen reference to laying a bead of modelling clay on the the flange and then trimming down to the flange while the part is still green however it would seem to me that the vacuum would squish out the clay? Can I use clay or would a strip of styrofoam layed along the part line work? I could bevel the edge of it outwards to give the excess cloth a place to rest while curing and then trim it off. The bottom line is that the two halves on completion must fit together perfectly as this is in carbon fibre and the seam will be very visible
We lay our carbon fibewr over the flange and then trim it with a knife in the green state. It works great for us. we put motorcycle parts together like this and the seem is near invisible.