I'm planning another attempt at lost foam casting tomorrow. The foam pattern is for a 10 inch wheel bench grinder guard and this time I've made some added three vents around the rim for excess aluminium and gasses to exit. My first attempt at this casting was made from expanded polystyrene and PVA glue which was a bit too flexible when burying in the sand and it failed as it wasn't deep enough in the sand to prevent a such a large area from developing pressure and leaking. This new version has yellow extruded polystyrene sheet and white expanded styrofoam glued with hot melt glue. What I'd appreciate guidance on is the pouring sprue, the last one was made from a few layers of foil which melted and collapsed fairly quickly. I have some 0.3mm soft sheet on a roll which I thought might last a bit longer during the pour but I'm completely ignorant about what's required regarding the sprue and the venting. Do I just have a short stub of foam and wrap the sheet tightly around the stub to form a cone to the surface for the sprue and the vents?. Does the loose sand need any venting anyway: I guess it would let you know you've poured enough metal when they melt. Any help will be greatly appreciated. Edit: I have watched Kelley's video on the topic of using the foil tape.