So after the pla/wax has been burned out and your about to pull the casting out to pour the metal about how long do you have to pour the metal? is there a temp you don't want the shell to fall under before pouring?

So I just want to make sure that I get this right. You do like 2 or 3 coats without sand to begin with. Also is timing super important here such as if I do lets say a few coats one day but then I cant get to it for lets say a week or it is good to just pick up where I left off