5/07/2011
Results were not as impressive as the melt. When I cut the gates to two of the (what I thought were good) ingots there was visible shrinkage. Matter of fact the whole ingot and gating system was hollow. I couldn’t have done that on purpose if I tried. The ingots looked perfectly good on the outside. I think it was caused by a combination of things, the first being that the pour temperature was too hot. The metal was shooting sparks, which is a sure sign of burning metal. The second thing is the straps securing the layers of the mold melted and released the pressure holding them together. This resulted in the metal surging out of the mold through the cracks. I think that this molten metal surging out of the mold actually pulled the still molten metal in the mold out with it, leaving only the cooling metal. The first metal to be poured and to touch the sand mold cooled and did not exit. These sand molds were not preheated in any way either, this also may be something to look into. To prevent the molds separating again, I have proposed to band the molds tight over angle iron along the length of the molds. Once tight weld the angle in place using ¼” round rod, just incase the metal flows over again melting the banding. To help prevent the metal flowing over again I also plan on using a larger pour cup.
Even though the ingots were not successful, I definitely feel that this was a huge learning experience. If I can figure out all the kinks of melting small amounts of scrap steel, the sky is the limit. Scrap steel is probably the most affordable and abundant metal available. To be able to melt and pour it into art or part on demand, I feel would be a huge advantage and again the possibilities are endless.
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