It has been a while since I have done any lost foam casting, but a recent request for a sign got me going on a slightly upsized set of flasks for sand casting with the lost foam method. I lost track of my original intention to document the process, as I was also using the brain for constructing the equipment and time kind of ran out. The actual pouring was pretty chaotic, but in the end the piece came out OK except for the top part where the speed of flow couldn't drive out the gases from the polystyrene out quickly enough leaving voids along the ridge.
Even sketches of the process of embedding the original and all the sprues and whatnot in sand might not be sufficient to convey sufficient detail to replicate the process, so perhaps the best solution will be to have another go one day soon and video it.
There is something odd about feeding the pot in the furnace while it is blasting away to melt the aluminium and also focusing on the job of jamming the sand in that leaves the brain with very little room for any other activity.
This piece is about 55x35cm, which is just about the limit for the new set of flasks. Anyway, after fitting the problems with the top hardly notice at all thanks to the position and the lighting.