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42755Re: Need advice

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  • Inventor
    Apr 10, 2013
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      Just a side thought:
      Did you de-gass before the pour?

      Grandpa Bill

      --- In hobbicast@yahoogroups.com, "crashbone256" <wheezer606@...> wrote:
      >
      > Group:
      >
      > I made the mold from eps. I taped the edges with masking tape.
      > I encased the mold in POP. The mold was oven dried at 170 F for 12 hours.
      > Then 8 hours at 200 F. Acetone was poured into the mold the dissolve the
      > styrofoam. The mold was dried at 210 F for 3 hours. The 200F molds were buried in new dry sand to near the top.
      >
      > 5 # Al muffins were melted in a 10 # crucible. The crux was red hot when removed.
      >
      > As the Al melt was poured into the "empty" mold it bubbled and popped and blew
      > bubbles up through the sprue. A steady stream was being poured, but it didn't want to go down the sprue.
      >
      > You can see from the first picture how it was gated.
      > Sprued on the top, Al runs down into the mold and rises off the bottom.
      >
      > The casting is porous and crappy.
      > What to do next time?
      >
      >
      > Thanks
      > lance
      > ++++
      >
      >
      > http://groups.yahoo.com/group/hobbicast/photos/album/1891226731/pic/list
      >
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