@Adelie:Check out these videos on youtube:
These are the videos that got me interested. I also read of someone else using PLA and investment, but he burned his PLA out as though it were wax. I was thinking that a hollow PLA piece done in investment would work as well as foam as long as there were enough vents. Using hot glued foam and drinking straws for the sprues/risers/vents lets you pour without making a two-part mold. I also saw a video on youtube that I can't find now (of course) where the person one-piece flask that was built with an air table in the bottom. When he turned on the air, he could sink the investment coated piece straight into the silica sand. Stopping the air and a few raps on the side set the sand tightly against the piece.
Thanks for the tip about the diamond blade and table saw. I wouldn't have thought of trying that one. Definitely an outdoors project ;-)
Metal casting harbors no secrets: If you can whittle a whistle, you can make a pattern, if you've ever built sand castles, you can make a mold and if you can boil water, you can melt metal and pour it into that mold. It really is that simple. if I could build a lathe using my new casting skills nothing would prevent me from going hog-wild and manufacturing all the other tools I needed to outfit my workshop.