In the warm weather I'm trying to cast early in the day. Should I expect to be able to make a mold late in the day and then have it perform well the next morning? So far I've been making up molds just before I heat the metal, or while the furnace is running. Another question, while I think I'm getting acceptable results, I have no way of knowing whether I'm ramming the sand too hard. It is right that if you don't have gas pockets the sand has adequate porosity? I try to get it pretty firm against the pattern.