I studied sand casting in the '90's as part of my manufacturing degree. It's best used for items that don't necessarily have a cosmetic requirement, like intake and exhaust manifolds which make use of machining operations to make them functional. For intricate parts with fine details, especially those that will be decoratively plated like emblems, letters, hood spears, etc., those are all die cast. The term "die" refers to a cavity made of steel specifically machined into a metal mold which is to be injected with whatever alloy is specified. The precision of the die is much like that built for plastic injection molded products that require good surface finish with little or no secondary machining operations afterwards. In short, high quality sand casting is great for functional parts that don't require anything cosmetic. Pretty parts come from die casting. Devon
Thanks Ponch, I have 4 or 5 from different years I was playing with. The 70 GS emblems were the ones I really wanted to work. Pour them with copper or brass and they will never pit.
Years ago I had the opportunity to tour the GM Tech center and also the Proving grounds. During the tech center visit I was able to watch them pour an aluminum head using the "lost foam" method. Sand was placed around a head made of polystyrene foam. There was a little nipple of the foam protruding from the sand. They would pour the molten aluminum on the protruding part of the foam and it would melt as the metal followed the foam core. The result was a piece so smooth that it only needed slight clean up. No flashing at all.
Now if I could only figure out how to make things I want to repro out of foam. Havent messed with it much lately but I did make 50lbs of copper ingots and around 40lb of brass ingots a few days ago. Why get .60 a lb for unclean brass when I can get 3.25 for clean ingots. seems lake a no brainer.
Got this in a email the other day; Not sure of the details, but the process might be along the lines of what you are looking for.
