![]() ![]() Totally defeats the repeat-use pattern approach, but perhaps ok for one-off castings. I see people spending significant amounts of time making one-off complex hardware store foam patterns, only to burn them up when they pour metal. The backyard-type hardware store foam method defeats the purpose of the lost foam method, since you have to create every pattern in foam, over and over again with each casting, instead of the industry method of using a metal mold and expanding polystyrene beads into the reusable mold. Lost foam is used successfully in industry with gray iron, but it is used with expanded polystyrene beads, and a special investment coating material. ![]() I saw one individual recently who tried the hardware store lost foam with gray iron, and it was a spectacular fail. The backyard application of hardware store foam is not really how lost-foam is done in industry, and so the quality of backyard lost foam castings can vary greatly. The backyard crowd uses hardware store foam, and while a few have had some success with this type of foam, often I see failures due to the foam not vaporizing very well, exessive gassing, interupted pours, thick toxic smoke, etc. The investment material used with lost foam is permeable so as to absorb both the gasses from vaporizing polystyrene, and also absorb liquids from melting polystyrene. The industrial lost-foam method uses polystyrene beads which are expanded with heat inside of a metal mold. I am also thinking of placing the investment mold inside of the furnace, and pouring the metal into the investment while it´s inside the furnace, would it make the aluminum flow better into the mold? Also, what is the superficial tension of the melted aluminum, and how one can make It flow towards the walls and edges of the mold? What is the most precise level of detail that I can achieve with this method? As I understand it, the metal has difficulties reaching thin and deep passages due to the thickening as it cools down. If someone has experience with similar types of castings, I would greatly appreciate your knowledge exchange. I thought of 3d printing a mold (considering the shrinkage), then covering the mold with investment plaster, burning it out of the investment, and finally pouring melted aluminum in it. and I want to experiment with casting my own engine block by using a lost wax method. I'm interested in creating my own scale 4-stroke engines. I'm now building my own furnace with a steel container, refractory ceramic blanket, and plaster walls. I recently bought an Emco Unimat 3 mini lathe. I'm 25 years old and finally have some resources to start this hobby. ![]()
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