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Re: [hobbicast] First sand cast: Cling wrap, short pour, and poor surface finish

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  • Chris Boyer (CB)
    ... From: Eric Poulsen To: Sent: Saturday, April 30, 2005 11:00 PM Subject: [hobbicast] First sand cast: Cling
    Message 1 of 10 , May 1, 2005
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      ----- Original Message -----
      From: "Eric Poulsen" <eric@...>
      To: <hobbicast@yahoogroups.com>
      Sent: Saturday, April 30, 2005 11:00 PM
      Subject: [hobbicast] First sand cast: Cling wrap, short pour, and poor
      surface finish


      > Aha! I have baby powder. Turns out that this doesn't work, at least
      > not the corn starch kind. After ramming up my mold, I couldn't even
      > separate the cope drop-out from the flattened drag sand; it had fused
      > into one.

      How much are you puting on?

      >
      > Since diatomaceous earth is one of those things that are supposedly
      > "easy to find," but don't actually exist in any real store, I couldn't
      > use that. So, I used what I had on hand -- plastic cling wrap.

      I know many say you can use this stuff. And yes it will work. Its not the
      best idea as it can cause lung problems.
      If you must have some or need to try it go to your local pool supplier (not
      wally world). They use it in the filters. Also can be had at good farm
      supply store.

      There are many forms of it. The most expensive being sold as pest control.


      >
      > I rammed up the drag, made sure it was flat, and laid down a sheet of
      > cling wrap. Placed my pattern (Gingery lathe foot) on, and rammed up
      > the cope. Lifted it off, and it came out pretty well. I packed the
      > inside of the pattern with sand, and tapped out the core, and simply
      > placed it on the drag after removing the cling wrap.
      >
      > I melted 3 mingots in the furnace, and simply poured. AAARRRGG! I
      > short-poured -- just below where the sprue ends. I should have melted 1
      > or 2 more mingots.
      >
      > Here's the result (besides the incomplete pour):
      >
      > The top and most of the side surfaces are very smooth and nice, but most
      > of the bottom was really rough.
      >
      > I'm assuming it's because the sand wasn't packed tightly enough? I
      > figure if my sand was too wet, or the Al too hot, it would have been
      > bumpy all over, right? There was no hissing or popping, and the sand
      > only steamed a little bit as it was cooling, after I poured.

      Could be not packed enough but more likely gas. The core in the Gingery
      foot gives off a lot of water (green sand? ) so vent WELL . :) Scratch
      vents work pretty good for this one.
    • Carl Wilhelm Soderstrom
      ... I used to work at a landscaping company, and we had bags of it for sale at the store. I used to sit on them at lunch break, and try to figure out where to
      Message 2 of 10 , May 1, 2005
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        On 05/01 11:57 , Chris Boyer (CB) wrote:
        > > Since diatomaceous earth is one of those things that are supposedly
        > > "easy to find," but don't actually exist in any real store
        > If you must have some or need to try it go to your local pool supplier (not
        > wally world). They use it in the filters. Also can be had at good farm
        > supply store.

        I used to work at a landscaping company, and we had bags of it for sale at
        the store. I used to sit on them at lunch break, and try to figure out where
        to get some nitroglycerin to mix with it. ;)

        --
        Carl Soderstrom

        "I love the way Microsoft follows standards. In much the
        same manner that fish follow migrating caribou."
        Paul Tomblin
      • Eric Poulsen
        ... Quite a bit. I think the fact that it s not talc might be the issue. ... I was trying garden stores and nurseries -- I ll check with the pool guys. ...
        Message 3 of 10 , May 1, 2005
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          Chris Boyer (CB) wrote:

          >>Aha! I have baby powder. Turns out that this doesn't work, at least
          >>not the corn starch kind. After ramming up my mold, I couldn't even
          >>separate the cope drop-out from the flattened drag sand; it had fused
          >>into one.
          >>
          >>
          >
          >How much are you puting on?
          >
          >
          Quite a bit. I think the fact that it's not talc might be the issue.

          >
          >
          >>Since diatomaceous earth is one of those things that are supposedly
          >>"easy to find," but don't actually exist in any real store, I couldn't
          >>use that. So, I used what I had on hand -- plastic cling wrap.
          >>
          >>
          >
          >I know many say you can use this stuff. And yes it will work. Its not the
          >best idea as it can cause lung problems.
          >If you must have some or need to try it go to your local pool supplier (not
          >wally world). They use it in the filters. Also can be had at good farm
          >supply store.
          >
          >There are many forms of it. The most expensive being sold as pest control.
          >
          >
          >
          I was trying garden stores and nurseries -- I'll check with the pool guys.

          >>I'm assuming it's because the sand wasn't packed tightly enough? I
          >>figure if my sand was too wet, or the Al too hot, it would have been
          >>bumpy all over, right? There was no hissing or popping, and the sand
          >>only steamed a little bit as it was cooling, after I poured.
          >>
          >>
          >
          >Could be not packed enough but more likely gas. The core in the Gingery
          >foot gives off a lot of water (green sand? ) so vent WELL . :) Scratch
          >vents work pretty good for this one.
          >
          >
          Yes, green sand. Vent the core itself? So that it can steam upwards
          until it's covered with aluminum? What's a Scratch Vent?
        • Chris Boyer (CB)
          ... From: Eric Poulsen To: Sent: Sunday, May 01, 2005 6:35 PM Subject: Re: [hobbicast] First sand cast: Cling
          Message 4 of 10 , May 1, 2005
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            ----- Original Message -----
            From: "Eric Poulsen" <eric@...>
            To: <hobbicast@yahoogroups.com>
            Sent: Sunday, May 01, 2005 6:35 PM
            Subject: Re: [hobbicast] First sand cast: Cling wrap, short pour, and poor
            surface finish
            >>How much are you puting on?
            >>
            >>
            > Quite a bit. I think the fact that it's not talc might be the issue.

            Only difference should be in the smell.
            Quite a bit is the clue that there may have been to much. :)
            It cakes up and makes a sticky mess if to much. LIGHT dusting.
            Baking soda works great and is free after its time in the fridge.
            Been using it for over 2 years since I started.

            >>>Since diatomaceous earth is one of those things that are supposedly
            >>>"easy to find," but don't actually exist in any real store, I couldn't
            >>>use that. So, I used what I had on hand -- plastic cling wrap.
            >>>
            >>I know many say you can use this stuff. And yes it will work. Its not
            >>the
            >>best idea as it can cause lung problems.
            >>If you must have some or need to try it go to your local pool supplier
            >>(not
            >>wally world). They use it in the filters. Also can be had at good farm
            >>supply store.
            >>
            >>There are many forms of it. The most expensive being sold as pest
            >>control.
            > I was trying garden stores and nurseries -- I'll check with the pool guys.

            Its used in the "in ground" pool filters. Was about $30 for 25 lb bag.
            IIRC.
            Gardeners use it to kill grubs, larva, flees. Tough on their skin and they
            ooze to death.
            Farmers use it to control the fly population(larva).

            DONT breathe the stuff any more than you have to.

            >>>I'm assuming it's because the sand wasn't packed tightly enough? I
            >>>figure if my sand was too wet, or the Al too hot, it would have been
            >>>bumpy all over, right? There was no hissing or popping, and the sand
            >>>only steamed a little bit as it was cooling, after I poured.
            >>>
            >>Could be not packed enough but more likely gas. The core in the Gingery
            >>foot gives off a lot of water (green sand? ) so vent WELL . :)
            >>Scratch
            >>vents work pretty good for this one.
            >>
            >>
            > Yes, green sand. Vent the core itself? So that it can steam upwards
            > until it's covered with aluminum? What's a Scratch Vent?

            No don't vent the core. Then it (aluminum) will blow back on you.
            I did the same procedure. Filled the bottom of the pattern and sat the core
            on top of the drag.
            Similar procedure for the bed so you don't have to roll that whole heavy
            mess over twice. :)
            I did run some vents about half way up the core. The water then runs down
            instead of steam up.

            Scratch vent is basically a line scratched on the drag (usually) from the
            pattern to the edge of the drag

            I like Gingery books but they leave out a lot of little details that could
            be useful. All in the learning.
            Don't feel bad I made 5 leg castings till I got 2 good ones :) Mine were
            about double sized though.
          • edi malinaric
            Hello Carl - please - when you start talking about mixing in NG - isn t it Kieselguhr?? Same stuff but sounds better - as though you really know what s going
            Message 5 of 10 , May 2, 2005
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              Hello Carl - please - when you start talking about mixing in NG - isn't it
              Kieselguhr?? Same stuff but sounds better - as though you really know what's
              going on!

              My first job was in the laboratory of an explosive factory that made that
              honey-coloured stuff. Ouch - that was in 1956 - guess the recall memory
              hasn't completely left me.


              ----- Original Message -----
              From: "Carl Wilhelm Soderstrom" <chrome@...>

              > > > <snip> diatomaceous earth
              > <snip>

              > I used to work at a landscaping company, and we had bags of it for sale at
              > the store. I used to sit on them at lunch break, and try to figure out
              where
              > to get some nitroglycerin to mix with it. ;)
              >
              > --
              > Carl Soderstrom
            • Carl Wilhelm Soderstrom
              ... heh. I suppose. :) http://nobelprize.org/nobel/alfred-nobel/industrial/krummel/kieselguhr.html -- Carl Soderstrom If we make enough laws, we will all be
              Message 6 of 10 , May 2, 2005
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                On 05/02 11:20 , edi malinaric wrote:
                > Hello Carl - please - when you start talking about mixing in NG - isn't it
                > Kieselguhr?? Same stuff but sounds better - as though you really know what's
                > going on!

                heh. I suppose. :)
                http://nobelprize.org/nobel/alfred-nobel/industrial/krummel/kieselguhr.html

                --
                Carl Soderstrom

                If we make enough laws, we will all be criminals.
              • Eric Poulsen
                ... Thanks for the tip on scratch vents. I ve also beefed up the legs -- I have 3/8 thick section, and made the legs and the bed 1 wider than the book. Did
                Message 7 of 10 , May 2, 2005
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                  >I like Gingery books but they leave out a lot of little details that could
                  >be useful. All in the learning.
                  >Don't feel bad I made 5 leg castings till I got 2 good ones :) Mine were
                  >about double sized though.
                  >
                  >
                  Thanks for the tip on scratch vents. I've also beefed up the legs -- I
                  have 3/8" thick section, and made the legs and the bed 1" wider than the
                  book. Did you have any trouble centering the cores in the proper location?
                • Daniel C Postellon
                  Lindsay Books used to sell stories of the oil industry in Pennsylvania, where they blow wells with nitroglycerine to improve oil recovery.
                  Message 8 of 10 , May 2, 2005
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                    Lindsay Books used to sell stories of the oil industry in Pennsylvania,
                    where they blow wells with nitroglycerine to improve oil recovery.
                    > On 05/02 11:20 , edi malinaric wrote:
                    >> Hello Carl - please - when you start talking about mixing in NG - isn't it
                    >> Kieselguhr?? Same stuff but sounds better - as though you really know what's
                    >> going on!
                    >
                    > heh. I suppose. :)
                    > http://nobelprize.org/nobel/alfred-nobel/industrial/krummel/kieselguhr.html
                    >
                    > --
                    > Carl Soderstrom
                    >
                    > If we make enough laws, we will all be criminals.
                    >
                    >
                    >
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                  • Chris Boyer (CB)
                    ... From: Eric Poulsen To: Sent: Monday, May 02, 2005 10:39 AM Subject: Re: [hobbicast] First sand cast: Cling
                    Message 9 of 10 , May 2, 2005
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                      ----- Original Message -----
                      From: "Eric Poulsen" <eric@...>
                      To: <hobbicast@yahoogroups.com>
                      Sent: Monday, May 02, 2005 10:39 AM
                      Subject: Re: [hobbicast] First sand cast: Cling wrap, short pour, and poor
                      surface finish


                      >
                      >>I like Gingery books but they leave out a lot of little details that could
                      >>be useful. All in the learning.
                      >>Don't feel bad I made 5 leg castings till I got 2 good ones :) Mine were
                      >>about double sized though.
                      >>
                      >>
                      > Thanks for the tip on scratch vents. I've also beefed up the legs -- I
                      > have 3/8" thick section, and made the legs and the bed 1" wider than the
                      > book. Did you have any trouble centering the cores in the proper
                      > location?

                      No trouble. My legs and bed were also 3/8 thick.
                      Ram a blank drag. Dust with parting.
                      Don't forget to vent the drag.
                      Place pattern and ram the cope.
                      You should end up with enough imprint to sit the core.
                      You can use a piece of wire to sit the core on to keep it from moving
                      around.
                      Same procedure for the bed. Since my bed was 36" I added a riser at each
                      end.
                      BUT I can melt enough AL to do that.
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