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Re: Need advice

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  • Inventor
    Just a side thought: Did you de-gass before the pour? Grandpa Bill
    Message 1 of 24 , 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
      >
    • StoneTool
      Mark: I think you misread.......... American Plaster is probably a company not a product. Though I wouldn t be surprised if during the Bush administration
      Message 2 of 24 , Apr 10, 2013
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        Mark:
        I think you misread.......... American Plaster is probably a
        company not a product. Though I wouldn't be surprised if during the
        Bush administration when they were stirring up hatred against the French
        for telling the truth, and going to such absurd lengths as renaming
        everything with the word "French", if Plaster of Paris wasn't renamed
        "American Plaster" along with the other childish nonsense that went on!

        Howard

        On 04/10/2013 09:42 AM, Yvanwolvesbane wrote:
        > Hey there, folks-
        > PoP I'm familiar with. This is the first time I've heard of American Plaster. Is it known by other names? What makes it different from PoP?
        >
        > Mark Feldmann/
        > Yvan Wolvesbane
        >
        > Pacifist with occasional lapses
        >
        >
        > On Apr 10, 2013, at 9:52 AM, Dan Brewer <danqualman@...> wrote:
        >
        >> On of the problems with using POP is that it is hygroscopic meaning that
        >> the material will never release all of the water trapped in its structure.
        >> It actually will draw water out of the atmosphere . I would use a material
        >> that when fired will vitrify and change to a substance that now will reject
        >> water. American plaster makes casting plaster. 50 lbs goes for about
        >> 20USD . There are several others. Plaster of Paris is best left to the
        >> art casting for statues.
        >>
        >> Dan in Auburn
        >>
        >>
        >> On Tue, Apr 9, 2013 at 10:07 PM, Eggleston Lance <wheezer606@...>wrote:
        >>
        >>> **
        >>>
        >>>
        >>> OK, will dry 400-700 F.
        >>>
        >>> Would it work better to fill from the bottom and
        >>> vent at the top ?
        >>>
        >>> lance
        >>> ++++
        >>>
        >>> On Apr 9, 2013, at 10:19 PM, Jeshua Lacock wrote:
        >>>
        >>>> Sounds like the POP had far too much water in it still.
        >>>>
        >>>> I would dry it out more around 400F. When I do lost plastic casting (a
        >>> bit different of course) I heat the POP mold up to around 1000F...
        >>>
        >>> [Non-text portions of this message have been removed]
        >>>
        >>>
        >>>
        >>
        >> [Non-text portions of this message have been removed]
        >>
        >>
        >>
        >> ------------------------------------
        >>
        >> For discussion of Metal Casting and related issues
        >> this list does not accept attachments.
        >>
        >> Files area and list services are at:
        >> http://groups.yahoo.com/group/hobbicast
        >>
        >> For additional files and photos and off topic discussions
        >> check out these two affiliated sites:
        >> http://groups.yahoo.com/group/sandcrabs
        >> http://groups.yahoo.com/group/Hobbicast1
        >>
        >> Please visit our sponsor: Budget Casting Supply
        >> http://budgetcastingsupply.com/
        >>
        >> List Owner:
        >> owly@...
        >>
        >> Yahoo! Groups Links
        >>
        >>
        >>
        >
        > ------------------------------------
        >
        > For discussion of Metal Casting and related issues
        > this list does not accept attachments.
        >
        > Files area and list services are at:
        > http://groups.yahoo.com/group/hobbicast
        >
        > For additional files and photos and off topic discussions
        > check out these two affiliated sites:
        > http://groups.yahoo.com/group/sandcrabs
        > http://groups.yahoo.com/group/Hobbicast1
        >
        > Please visit our sponsor: Budget Casting Supply
        > http://budgetcastingsupply.com/
        >
        > List Owner:
        > owly@...
        >
        > Yahoo! Groups Links
        >
        >
        >
        >
      • Dan Brewer
        The big difference is that when fired the substrate will no longer adsorb any moisture. The term used to describe it is vitrification or to become like glass.
        Message 3 of 24 , Apr 10, 2013
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          The big difference is that when fired the substrate will no longer adsorb
          any moisture. The term used to describe it is vitrification or to become
          like glass.


          On Wed, Apr 10, 2013 at 8:42 AM, Yvanwolvesbane <yvanwolvesbane222@...
          > wrote:

          > **
          >
          >
          > Hey there, folks-
          > PoP I'm familiar with. This is the first time I've heard of American
          > Plaster. Is it known by other names? What makes it different from PoP?
          >
          > Mark Feldmann/
          > Yvan Wolvesbane
          >
          > Pacifist with occasional lapses
          >
          >
          > On Apr 10, 2013, at 9:52 AM, Dan Brewer <danqualman@...> wrote:
          >
          > > On of the problems with using POP is that it is hygroscopic meaning that
          > > the material will never release all of the water trapped in its
          > structure.
          > > It actually will draw water out of the atmosphere . I would use a
          > material
          > > that when fired will vitrify and change to a substance that now will
          > reject
          > > water. American plaster makes casting plaster. 50 lbs goes for about
          > > 20USD . There are several others. Plaster of Paris is best left to the
          > > art casting for statues.
          > >
          > > Dan in Auburn
          > >
          > >
          > > On Tue, Apr 9, 2013 at 10:07 PM, Eggleston Lance <wheezer606@...
          > >wrote:
          > >
          > >> **
          >
          > >>
          > >>
          > >> OK, will dry 400-700 F.
          > >>
          > >> Would it work better to fill from the bottom and
          > >> vent at the top ?
          > >>
          > >> lance
          > >> ++++
          > >>
          > >> On Apr 9, 2013, at 10:19 PM, Jeshua Lacock wrote:
          > >>
          > >>> Sounds like the POP had far too much water in it still.
          > >>>
          > >>> I would dry it out more around 400F. When I do lost plastic casting (a
          > >> bit different of course) I heat the POP mold up to around 1000F...
          > >>
          > >> [Non-text portions of this message have been removed]
          > >>
          > >>
          > >>
          > >
          > >
          > > [Non-text portions of this message have been removed]
          > >
          > >
          > >
          > > ------------------------------------
          >
          > >
          > > For discussion of Metal Casting and related issues
          > > this list does not accept attachments.
          > >
          > > Files area and list services are at:
          > > http://groups.yahoo.com/group/hobbicast
          > >
          > > For additional files and photos and off topic discussions
          > > check out these two affiliated sites:
          > > http://groups.yahoo.com/group/sandcrabs
          > > http://groups.yahoo.com/group/Hobbicast1
          > >
          > > Please visit our sponsor: Budget Casting Supply
          > > http://budgetcastingsupply.com/
          > >
          > > List Owner:
          > > owly@...
          > >
          > > Yahoo! Groups Links
          > >
          > >
          > >
          >
          >
          >


          [Non-text portions of this message have been removed]
        • Yvanwolvesbane
          Thanks, Dan. That was very clear & warrants further investigation. Mark Feldmann/ Yvan Wolvesbane Pacifist ...with occasional lapses.
          Message 4 of 24 , Apr 10, 2013
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            Thanks, Dan. That was very clear & warrants further investigation.

            Mark Feldmann/
            Yvan Wolvesbane

            Pacifist ...with occasional lapses.


            On Apr 10, 2013, at 4:21 PM, Dan Brewer <danqualman@...> wrote:

            > The big difference is that when fired the substrate will no longer adsorb
            > any moisture. The term used to describe it is vitrification or to become
            > like glass.
            >>
            >>
            >>
            >>
            >>
            >>
            >>>
            >>>
            >>>
            >>>>
            >>>>
            >>>>
            >>>>
            >>>>
            >>>>>
            >>>>
            >>>>
            >>>>
            >>>>
            >>>
            >>>
            >>>
            >>>
            >>>
            >>>
            >>>
            >>>
            >>>
            >>>
            >>>
            >>>
            >>>
            >>>
            >>
            >>
            >>
          • Inventor
            Hey Dan, About a half a dozen links wouldn t hurt.... A few to read up about it. A few more as to where to buy it for 20 BUCKS All I ve found was clay and
            Message 5 of 24 , Apr 11, 2013
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              Hey Dan,
              About a half a dozen links wouldn't hurt....
              A few to read up about it.
              A few more as to where to buy it for "20 BUCKS"

              All I've found was clay and that 'started' at $85/50#.

              Grandpa Bill

              --- In hobbicast@yahoogroups.com, Dan Brewer <danqualman@...> wrote:
              >
              > On of the problems with using POP is that it is hygroscopic meaning that
              > the material will never release all of the water trapped in its structure.
              > It actually will draw water out of the atmosphere . I would use a material
              > that when fired will vitrify and change to a substance that now will reject
              > water. American plaster makes casting plaster. 50 lbs goes for about
              > 20USD . There are several others. Plaster of Paris is best left to the
              > art casting for statues.
              >
              > Dan in Auburn
            • Dan Brewer
              So here is a link to one supplier. http://www.sheffield-pottery.com/U-S-Gypsum-1-CASTING-PLASTER-50-lbs-p/rmcaspla50.htm The name of the company is US gypsum
              Message 6 of 24 , Apr 11, 2013
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                So here is a link to one supplier.
                http://www.sheffield-pottery.com/U-S-Gypsum-1-CASTING-PLASTER-50-lbs-p/rmcaspla50.htm
                The name of the company is US gypsum not US plaster. Brain fart. The way
                that I use it is to take my wax master with sprus and vent attached and
                coat it in Jet dry. Yes the stuff you use in your dish washer. It breaks
                the surface tension on the wax and allows the plaster to stick. I mix a
                little of the plaster up to the consistency of thin pancake batter and
                paint it on. until I have coated the entire master except the top of the
                pouring cup and the top of the vents. . I let that dry a little miz a
                little more up a little thicker and put on another coat. When still wet I
                sprinkle flint sand on the entire piece. Let that dry for a little. Mix up
                some more plaster about 60/40 plaster sand and coat the piece. Let dry. You
                should have coated the piece about 1.4 to 1/2 inch thick by now. Mix up
                some more plaster 50/50 sand and plaster. sprinkle each coat with sand. The
                next coat should be 30/30/30 plaster /sand / and grog. Grog is previously
                fired plaster that has been broken up in to pieces that will fit through a
                #8 sieve. When you have 3/4 to one inch of plaster wrap the piece in small
                chicken wire. This is to keep the mold from breaking up when you fire it.
                Add another inch of plaster , grog, sand to the outside of the mold. The
                top and bottom of the mold should be able to support the mold with out
                tipping over. The top because when you fire it the top will be down so all
                of the wax will leave the mold and the bottom so you can fill the now
                vacated mold with metal. Let dry .for several days in a warm spot. I place
                mine on a blotter board. My blotter board is a 2x2 piece of drywall.
                Place in your kiln and heat at the rate of 100 deg f per hour until the
                melting temp of the wax has been reached. My kiln has a stainless steel
                sink in the bottom that is plumbed out the bottom to get some of the wax
                out of the kiln. I am able to recover some of it but not much. after the
                wax is out around 200 to 275 deg you can ramp up a little faster Fire at
                2000deg f for 4 to 20 hours depending on size of the piece. Let cool to
                around 400 deg and pour.. Cover the pouring cup and vents with perlite or
                vermiculite and let cool. When the outside of the mold is just hot enough
                to touch sweep off the perlite/ vermiculite and you can remove the
                plaster. Remember that it will be hot. I use a hammer and a water hose to
                remove most of the plaster . Plaster will clog your drain . More clean up
                can be done with a stiff brush or sand blasting.
                For more information look up lost wax casting , ceramic shell casting.

                Dan in Auburn

                Other places to find casting plaster are pottery suppl houses. jewelery
                supply houses. And there are lots of formulas of the casting plaster. This
                is just the one that I have been using.


                On Thu, Apr 11, 2013 at 11:56 AM, Inventor <welfab@...> wrote:

                > **
                >
                >
                > Hey Dan,
                > About a half a dozen links wouldn't hurt....
                > A few to read up about it.
                > A few more as to where to buy it for "20 BUCKS"
                >
                > All I've found was clay and that 'started' at $85/50#.
                >
                > Grandpa Bill
                >
                >
                > --- In hobbicast@yahoogroups.com, Dan Brewer <danqualman@...> wrote:
                > >
                > > On of the problems with using POP is that it is hygroscopic meaning that
                > > the material will never release all of the water trapped in its
                > structure.
                > > It actually will draw water out of the atmosphere . I would use a
                > material
                > > that when fired will vitrify and change to a substance that now will
                > reject
                > > water. American plaster makes casting plaster. 50 lbs goes for about
                > > 20USD . There are several others. Plaster of Paris is best left to the
                > > art casting for statues.
                > >
                > > Dan in Auburn
                >
                >
                >


                [Non-text portions of this message have been removed]
              • abascirocco
                FWIW, US Gypsum also has a plaster specifically formulated for non-ferrous metal casting, they call it simply USG metal casting plaster. The other major North
                Message 7 of 24 , Apr 11, 2013
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                  FWIW, US Gypsum also has a plaster specifically formulated for non-ferrous metal casting, they call it simply USG metal casting plaster. The other major North American plaster manufacturer is Georgia Pacific, they also have a line of metal casting plasters.



                  --- In hobbicast@yahoogroups.com, Dan Brewer <danqualman@...> wrote:
                  >
                  > So here is a link to one supplier.
                  > http://www.sheffield-pottery.com/U-S-Gypsum-1-CASTING-PLASTER-50-lbs-p/rmcaspla50.htm
                  > The name of the company is US gypsum not US plaster. Brain fart. The way
                  > that I use it is to take my wax master with sprus and vent attached and
                  > coat it in Jet dry. Yes the stuff you use in your dish washer. It breaks
                  > the surface tension on the wax and allows the plaster to stick. I mix a
                  > little of the plaster up to the consistency of thin pancake batter and
                  > paint it on. until I have coated the entire master except the top of the
                  > pouring cup and the top of the vents. . I let that dry a little miz a
                  > little more up a little thicker and put on another coat. When still wet I
                  > sprinkle flint sand on the entire piece. Let that dry for a little. Mix up
                  > some more plaster about 60/40 plaster sand and coat the piece. Let dry. You
                  > should have coated the piece about 1.4 to 1/2 inch thick by now. Mix up
                  > some more plaster 50/50 sand and plaster. sprinkle each coat with sand. The
                  > next coat should be 30/30/30 plaster /sand / and grog. Grog is previously
                  > fired plaster that has been broken up in to pieces that will fit through a
                  > #8 sieve. When you have 3/4 to one inch of plaster wrap the piece in small
                  > chicken wire. This is to keep the mold from breaking up when you fire it.
                  > Add another inch of plaster , grog, sand to the outside of the mold. The
                  > top and bottom of the mold should be able to support the mold with out
                  > tipping over. The top because when you fire it the top will be down so all
                  > of the wax will leave the mold and the bottom so you can fill the now
                  > vacated mold with metal. Let dry .for several days in a warm spot. I place
                  > mine on a blotter board. My blotter board is a 2x2 piece of drywall.
                  > Place in your kiln and heat at the rate of 100 deg f per hour until the
                  > melting temp of the wax has been reached. My kiln has a stainless steel
                  > sink in the bottom that is plumbed out the bottom to get some of the wax
                  > out of the kiln. I am able to recover some of it but not much. after the
                  > wax is out around 200 to 275 deg you can ramp up a little faster Fire at
                  > 2000deg f for 4 to 20 hours depending on size of the piece. Let cool to
                  > around 400 deg and pour.. Cover the pouring cup and vents with perlite or
                  > vermiculite and let cool. When the outside of the mold is just hot enough
                  > to touch sweep off the perlite/ vermiculite and you can remove the
                  > plaster. Remember that it will be hot. I use a hammer and a water hose to
                  > remove most of the plaster . Plaster will clog your drain . More clean up
                  > can be done with a stiff brush or sand blasting.
                  > For more information look up lost wax casting , ceramic shell casting.
                  >
                  > Dan in Auburn
                  >
                  > Other places to find casting plaster are pottery suppl houses. jewelery
                  > supply houses. And there are lots of formulas of the casting plaster. This
                  > is just the one that I have been using.
                  >
                  >
                  > On Thu, Apr 11, 2013 at 11:56 AM, Inventor <welfab@...> wrote:
                  >
                  > > **
                  > >
                  > >
                  > > Hey Dan,
                  > > About a half a dozen links wouldn't hurt....
                  > > A few to read up about it.
                  > > A few more as to where to buy it for "20 BUCKS"
                  > >
                  > > All I've found was clay and that 'started' at $85/50#.
                  > >
                  > > Grandpa Bill
                  > >
                  > >
                  > > --- In hobbicast@yahoogroups.com, Dan Brewer <danqualman@> wrote:
                  > > >
                  > > > On of the problems with using POP is that it is hygroscopic meaning that
                  > > > the material will never release all of the water trapped in its
                  > > structure.
                  > > > It actually will draw water out of the atmosphere . I would use a
                  > > material
                  > > > that when fired will vitrify and change to a substance that now will
                  > > reject
                  > > > water. American plaster makes casting plaster. 50 lbs goes for about
                  > > > 20USD . There are several others. Plaster of Paris is best left to the
                  > > > art casting for statues.
                  > > >
                  > > > Dan in Auburn
                  > >
                  > >
                  > >
                  >
                  >
                  > [Non-text portions of this message have been removed]
                  >
                • bs190815
                  For years I have been using Ransom & Randoph Ultra-Vest. I recently bought five 100 pound drum; I use nothing else! Here is their web site, lots of good
                  Message 8 of 24 , Apr 18, 2013
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                    For years I have been using Ransom & Randoph Ultra-Vest. I recently bought five 100 pound drum; I use nothing else!

                    Here is their web site, lots of good information.

                    http://www.ransom-randolph.com/
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