I have tried many different ways to ventilate, but the most effective way so far is to connect 3 bathroom ceiling fans and hang them directly over the pots about 12 inches from the top. This sucks all the fumes out and through flexible metal dryer tubes and out the door of the garage. I then keep another small fan on to blow any extra smoke or fumes coming from the molds after they are poured. You can't tell I'm pouring in the garage unless you are standing outside where the exhaust is blowing. I side note...you must seal all the seams on the fans so they don't blow down on you or your on your work. I will try to submit a pic of the fans.