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Spray type mold release?

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  • creepinogie
    Folks, I m casting a batch of air cooled heads with long deep closely spaced fins. In short, I m having a hard time getting the pattern to release. I m using
    Message 1 of 15 , Oct 1, 2012
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      Folks,
      I'm casting a batch of air cooled heads with long deep closely spaced fins. In short, I'm having a hard time getting the pattern to release. I'm using threaded holes in the backside of the pattern that I screw threaded rods into, then they go through a plate and I extract the pattern with thumbscrews for an even draw. But the withdrawl is hard. I've been using Johnson paste wax and some silicon spray mold release but it's not working as well as I had hoped.

      Any suggestions would be appreciated. Thanks.
      LL
    • Jim Rogers
      I would think that the wax and silicone would stick to the sand, one thing I do on my troublesome patterns is spray them with a rubbing alcohol/graphite dust
      Message 2 of 15 , Oct 1, 2012
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        I would think that the wax and silicone would stick to the sand, one
        thing I do on my troublesome patterns is spray them with a rubbing
        alcohol/graphite dust mix, let that dry, and then dust with more
        graphite or parting powder again. The pros use air vibrators on their
        match plates to help release the patterns from the sand, I sometimes use
        one of those electric auto-hammers on mine, have you tried anything like
        that?

        jr

        On 10/1/12 8:56 AM, creepinogie wrote:
        > Folks,
        > I'm casting a batch of air cooled heads with long deep closely spaced fins. In short, I'm having a hard time getting the pattern to release. I'm using threaded holes in the backside of the pattern that I screw threaded rods into, then they go through a plate and I extract the pattern with thumbscrews for an even draw. But the withdrawl is hard. I've been using Johnson paste wax and some silicon spray mold release but it's not working as well as I had hoped.
        >
        > Any suggestions would be appreciated. Thanks.
        > LL
        >
        >

        --


        [Non-text portions of this message have been removed]
      • Lyle
        JR, One problem is these are loose patterns which is one reason for my 4 threaded holes and rods method of drawing the pattern. I have used johnson floor wax
        Message 3 of 15 , Oct 1, 2012
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          JR, One problem is these are loose patterns which is one reason for my 4 threaded holes and rods method of drawing the pattern. I have used johnson floor wax sucessfully for OHV engine heads but the finning was far less complicated. You can make an electric vibrator from an orbital hand sander by using a stud on the bottom of the plate that goes into a hole in the corner of the matchplate. Personally, all my matchplate work is done with petrobond (not the heads) and I just rap the sides of the matchplate.

          --- In hobbicast@yahoogroups.com, Jim Rogers <jr@...> wrote:
          >
          > I would think that the wax and silicone would stick to the sand, one
          > thing I do on my troublesome patterns is spray them with a rubbing
          > alcohol/graphite dust mix, let that dry, and then dust with more
          > graphite or parting powder again. The pros use air vibrators on their
          > match plates to help release the patterns from the sand, I sometimes use
          > one of those electric auto-hammers on mine, have you tried anything like
          > that?
          >
          > jr
          >
          > On 10/1/12 8:56 AM, creepinogie wrote:
          > > Folks,
          > > I'm casting a batch of air cooled heads with long deep closely spaced fins. In short, I'm having a hard time getting the pattern to release. I'm using threaded holes in the backside of the pattern that I screw threaded rods into, then they go through a plate and I extract the pattern with thumbscrews for an even draw. But the withdrawl is hard. I've been using Johnson paste wax and some silicon spray mold release but it's not working as well as I had hoped.
          > >
          > > Any suggestions would be appreciated. Thanks.
          > > LL
          > >
          > >
          >
          > --
          >
          >
          > [Non-text portions of this message have been removed]
          >
        • walter peterson
          I know that Caterpillar has a Graphite spray for lubing certain moving parts...you could probably find something like that at NAPA   ... From: creepinogie
          Message 4 of 15 , Oct 1, 2012
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            I know that Caterpillar has a Graphite spray for lubing certain moving parts...you could probably find something like that at NAPA

             

            --- On Mon, 10/1/12, creepinogie <creepinogie@...> wrote:

            From: creepinogie <creepinogie@...>
            Subject: [hobbicast] Spray type mold release?
            To: hobbicast@yahoogroups.com
            Date: Monday, October 1, 2012, 9:56 AM
















             









            Folks,

            I'm casting a batch of air cooled heads with long deep closely spaced fins. In short, I'm having a hard time getting the pattern to release. I'm using threaded holes in the backside of the pattern that I screw threaded rods into, then they go through a plate and I extract the pattern with thumbscrews for an even draw. But the withdrawl is hard. I've been using Johnson paste wax and some silicon spray mold release but it's not working as well as I had hoped.



            Any suggestions would be appreciated. Thanks.

            LL



























            [Non-text portions of this message have been removed]
          • Nelson Collar
            If you get the graphit spray it will not work because you need to burn in the graphite. Nelson Collar ________________________________ From: walter peterson
            Message 5 of 15 , Oct 1, 2012
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              If you get the graphit spray it will not work because you need to burn in the graphite.
              Nelson Collar


              ________________________________
              From: walter peterson <walt4711@...>
              To: hobbicast@yahoogroups.com
              Sent: Monday, October 1, 2012 7:42 PM
              Subject: Re: [hobbicast] Spray type mold release?



               

              I know that Caterpillar has a Graphite spray for lubing certain moving parts...you could probably find something like that at NAPA

               

              --- On Mon, 10/1/12, creepinogie <mailto:creepinogie%40yahoo.com> wrote:

              From: creepinogie <mailto:creepinogie%40yahoo.com>
              Subject: [hobbicast] Spray type mold release?
              To: mailto:hobbicast%40yahoogroups.com
              Date: Monday, October 1, 2012, 9:56 AM

               

              Folks,

              I'm casting a batch of air cooled heads with long deep closely spaced fins. In short, I'm having a hard time getting the pattern to release. I'm using threaded holes in the backside of the pattern that I screw threaded rods into, then they go through a plate and I extract the pattern with thumbscrews for an even draw. But the withdrawl is hard. I've been using Johnson paste wax and some silicon spray mold release but it's not working as well as I had hoped.

              Any suggestions would be appreciated. Thanks.

              LL

              [Non-text portions of this message have been removed]




              [Non-text portions of this message have been removed]
            • Nelson Collar
              creepin I should have read you first message. If you want to pour very thin fins, you will need a core that when cured will release from your mold. Then you
              Message 6 of 15 , Oct 1, 2012
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                creepin
                I should have read you first message. If you want to pour very thin fins, you will need a core that when cured will release from your mold. Then you can cast it. But usually the fins are cut on the lathe.
                Nelson Collar


                ________________________________
                From: walter peterson <walt4711@...>
                To: hobbicast@yahoogroups.com
                Sent: Monday, October 1, 2012 7:42 PM
                Subject: Re: [hobbicast] Spray type mold release?



                 

                I know that Caterpillar has a Graphite spray for lubing certain moving parts...you could probably find something like that at NAPA

                 

                --- On Mon, 10/1/12, creepinogie <mailto:creepinogie%40yahoo.com> wrote:

                From: creepinogie <mailto:creepinogie%40yahoo.com>
                Subject: [hobbicast] Spray type mold release?
                To: mailto:hobbicast%40yahoogroups.com
                Date: Monday, October 1, 2012, 9:56 AM

                 

                Folks,

                I'm casting a batch of air cooled heads with long deep closely spaced fins. In short, I'm having a hard time getting the pattern to release. I'm using threaded holes in the backside of the pattern that I screw threaded rods into, then they go through a plate and I extract the pattern with thumbscrews for an even draw. But the withdrawl is hard. I've been using Johnson paste wax and some silicon spray mold release but it's not working as well as I had hoped.

                Any suggestions would be appreciated. Thanks.

                LL

                [Non-text portions of this message have been removed]




                [Non-text portions of this message have been removed]
              • Lyle
                Nelson, These are heads, not cylinders. They are old patterns that were used decades ago. I have made cylinder patterns on a wood lathe and they were cast in
                Message 7 of 15 , Oct 2, 2012
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                  Nelson,
                  These are heads, not cylinders. They are old patterns that were used decades ago. I have made cylinder patterns on a wood lathe and they were cast in Co2 sand with good results. These are totally different.
                  My problem is probably a combination of a few things, mixing the sand too rich, release agent, not enough rapping prior to the sand setting up, etc.
                  LL



                  --- In hobbicast@yahoogroups.com, Nelson Collar <nel2lar@...> wrote:
                  >
                  > creepin
                  > I should have read you first message. If you want to pour very thin fins, you will need a core that when cured will release from your mold. Then you can cast it. But usually the fins are cut on the lathe.
                  > Nelson Collar
                  >
                  >
                  > ________________________________
                  > From: walter peterson <walt4711@...>
                  > To: hobbicast@yahoogroups.com
                  > Sent: Monday, October 1, 2012 7:42 PM
                  > Subject: Re: [hobbicast] Spray type mold release?
                  >
                  >
                  >
                  >  
                  >
                  > I know that Caterpillar has a Graphite spray for lubing certain moving parts...you could probably find something like that at NAPA
                  >
                  >  
                  >
                  > --- On Mon, 10/1/12, creepinogie <mailto:creepinogie%40yahoo.com> wrote:
                  >
                  > From: creepinogie <mailto:creepinogie%40yahoo.com>
                  > Subject: [hobbicast] Spray type mold release?
                  > To: mailto:hobbicast%40yahoogroups.com
                  > Date: Monday, October 1, 2012, 9:56 AM
                  >
                  >  
                  >
                  > Folks,
                  >
                  > I'm casting a batch of air cooled heads with long deep closely spaced fins. In short, I'm having a hard time getting the pattern to release. I'm using threaded holes in the backside of the pattern that I screw threaded rods into, then they go through a plate and I extract the pattern with thumbscrews for an even draw. But the withdrawl is hard. I've been using Johnson paste wax and some silicon spray mold release but it's not working as well as I had hoped.
                  >
                  > Any suggestions would be appreciated. Thanks.
                  >
                  > LL
                  >
                  > [Non-text portions of this message have been removed]
                  >
                  >
                  >
                  >
                  > [Non-text portions of this message have been removed]
                  >
                • tiwonk
                  Be sure your pattern fins are very smooth and clean, Clean well with alcohol and I would try some welders marker soap stone ground to a powder in a pencil
                  Message 8 of 15 , Oct 2, 2012
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                    Be sure your pattern fins are very smooth and clean, Clean well with alcohol and I would try some welders marker soap stone ground to a powder in a pencil sharpener to use as a parting agent. I use a small bush to rub it into all the crevices and hard to reach places. It is about the same as graphite but much cleaner to work with!

                    Wonk


                    --- In hobbicast@yahoogroups.com, "Lyle" <creepinogie@...> wrote:
                    >
                    > Nelson,
                    > These are heads, not cylinders. They are old patterns that were used decades ago. I have made cylinder patterns on a wood lathe and they were cast in Co2 sand with good results. These are totally different.
                    > My problem is probably a combination of a few things, mixing the sand too rich, release agent, not enough rapping prior to the sand setting up, etc.
                    > LL
                    >
                    >
                    >
                    > > I'm casting a batch of air cooled heads with long deep closely spaced fins. In short, I'm having a hard time getting the pattern to release. I'm using threaded holes in the backside of the pattern that I screw threaded rods into, then they go through a plate and I extract the pattern with thumbscrews for an even draw. But the withdrawl is hard. I've been using Johnson paste wax and some silicon spray mold release but it's not working as well as I had hoped.
                    > >
                    > > Any suggestions would be appreciated. Thanks.
                    > >
                    > > LL
                  • Rupert
                    Lyle, Just a thought. (I know that s dangerous) I understand your using a resin set sand. Would it be possible to use the fins to shape individual cores? Then
                    Message 9 of 15 , Oct 2, 2012
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                      Lyle,
                      Just a thought. (I know that's dangerous)
                      I understand your using a resin set sand. Would it be possible to use
                      the fins to shape individual cores? Then use the head to hold the cores
                      while you fill the rest of the flask. I think the resin set will bond to
                      the edges of the cores. I know that's lots of work but the idea has
                      worked for me a couple of times where I needed a thin section core.

                      Rupert
                      Ps. Rap the head a bit to loosen the cores before you gas them.

                      On 10/2/2012 7:15 AM, Lyle wrote:
                      > Nelson, These are heads, not cylinders. They are old patterns that
                      > were used decades ago. I have made cylinder patterns on a wood lathe
                      > and they were cast in Co2 sand with good results. These are totally
                      > different. My problem is probably a combination of a few things,
                      > mixing the sand too rich, release agent, not enough rapping prior to
                      > the sand setting up, etc.
                      >
                      > LL
                      >
                      >
                      --

                      yvt

                      Rupert Wenig
                      Camrose, Alberta, Canada.

                      email: rwenig2@...

                      http://users.xplornet.com/~rwenig/Home/
                    • Lyle
                      Rupert, Thanks for the idea but the pattern is one piece. Today after work I used a masonery bit to free the pattern out of the sand which looked a little like
                      Message 10 of 15 , Oct 2, 2012
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                        Rupert,
                        Thanks for the idea but the pattern is one piece. Today after work I used a masonery bit to free the pattern out of the sand which looked a little like sandstone. I have another oil cooler pattern which has similar depth fins but not as many that I used as an experiment for the head castings. I am going to try a reduced amount of binder to see if that helps and less ramming of the sand. Usually deep fins need to be jolted, which I did, but I also rammed, so I'll try jolting. the learning continues....Part of the problem is me using Johnson paste wax as a release but it's hard to get it between all the fins which are about 1/4" apart and 2" deep.
                        LL



                        --- In hobbicast@yahoogroups.com, Rupert <rwenig2@...> wrote:
                        >
                        > Lyle,
                        > Just a thought. (I know that's dangerous)
                        > I understand your using a resin set sand. Would it be possible to use
                        > the fins to shape individual cores? Then use the head to hold the cores
                        > while you fill the rest of the flask. I think the resin set will bond to
                        > the edges of the cores. I know that's lots of work but the idea has
                        > worked for me a couple of times where I needed a thin section core.
                        >
                        > Rupert
                        > Ps. Rap the head a bit to loosen the cores before you gas them.
                        >
                        > On 10/2/2012 7:15 AM, Lyle wrote:
                        > > Nelson, These are heads, not cylinders. They are old patterns that
                        > > were used decades ago. I have made cylinder patterns on a wood lathe
                        > > and they were cast in Co2 sand with good results. These are totally
                        > > different. My problem is probably a combination of a few things,
                        > > mixing the sand too rich, release agent, not enough rapping prior to
                        > > the sand setting up, etc.
                        > >
                        > > LL
                        > >
                        > >
                        > --
                        >
                        > yvt
                        >
                        > Rupert Wenig
                        > Camrose, Alberta, Canada.
                        >
                        > email: rwenig2@...
                        >
                        > http://users.xplornet.com/~rwenig/Home/
                        >
                      • StoneTool
                        Just thinking......... someone in a recent post said that was dangerous ;-) ............... Suppose you were able to coat the pattern with some sort of low
                        Message 11 of 15 , Oct 3, 2012
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                          Just thinking......... someone in a recent post said that was dangerous
                          ;-) ............... Suppose you were able to coat the pattern with
                          some sort of low melt temp wax in the critical areas to a perhaps by
                          dipping as in candle making. Then ram it up, and bake the works... The
                          wax would melt into the sand, and release from the pattern.... maybe.
                          The object being to end up with a few thousandth clearance so things
                          would come apart.

                          There are waxes that melt down around 120 degrees....

                          ]On 10/02/2012 09:27 PM, Lyle wrote:
                          > Rupert,
                          > Thanks for the idea but the pattern is one piece. Today after work I used a masonery bit to free the pattern out of the sand which looked a little like sandstone. I have another oil cooler pattern which has similar depth fins but not as many that I used as an experiment for the head castings. I am going to try a reduced amount of binder to see if that helps and less ramming of the sand. Usually deep fins need to be jolted, which I did, but I also rammed, so I'll try jolting. the learning continues....Part of the problem is me using Johnson paste wax as a release but it's hard to get it between all the fins which are about 1/4" apart and 2" deep.
                          > LL
                          >
                          >
                          >
                          > --- In hobbicast@yahoogroups.com, Rupert<rwenig2@...> wrote:
                          >> Lyle,
                          >> Just a thought. (I know that's dangerous)
                          >> I understand your using a resin set sand. Would it be possible to use
                          >> the fins to shape individual cores? Then use the head to hold the cores
                          >> while you fill the rest of the flask. I think the resin set will bond to
                          >> the edges of the cores. I know that's lots of work but the idea has
                          >> worked for me a couple of times where I needed a thin section core.
                          >>
                          >> Rupert
                          >> Ps. Rap the head a bit to loosen the cores before you gas them.
                          >>
                          >> On 10/2/2012 7:15 AM, Lyle wrote:
                          >>> Nelson, These are heads, not cylinders. They are old patterns that
                          >>> were used decades ago. I have made cylinder patterns on a wood lathe
                          >>> and they were cast in Co2 sand with good results. These are totally
                          >>> different. My problem is probably a combination of a few things,
                          >>> mixing the sand too rich, release agent, not enough rapping prior to
                          >>> the sand setting up, etc.
                          >>>
                          >>> LL
                          >>>
                          >>>
                          >> --
                          >>
                          >> yvt
                          >>
                          >> Rupert Wenig
                          >> Camrose, Alberta, Canada.
                          >>
                          >> email: rwenig2@...
                          >>
                          >> http://users.xplornet.com/~rwenig/Home/
                          >>
                          >
                          >
                          >
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                        • Rupert
                          Hello Lyle, My words weren t clear and I assumed your using sodium silicate sand. Johnson s paste wax should work as long as you have complete coverage. I
                          Message 12 of 15 , Oct 3, 2012
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                            Hello Lyle,
                            My words weren't clear and I assumed your using sodium silicate sand.
                            Johnson's paste wax should work as long as you have complete coverage. I
                            meant to fill the spaces between the fins with the SS sand, pack it only
                            firmly (don't ram it). Rap the head on the side so the sand loosens a
                            bit. Then, gas it to harden. I think the hardened mix should fall out.
                            Do this for every space. Place them in place between the fins and make
                            the complete mold again using SS sand as it should bind to the
                            previously made fin cores. Only a firm packing is needed- don't ram it.
                            Again, rap the head enough to loosen it before gassing. The head should
                            fall out when you turn the flask over provided there are no undercuts to
                            consider. Don't know if this will work with other types of resin set
                            sands. But, I do think the SS sand should work.

                            Rupert

                            On 10/2/2012 9:27 PM, Lyle wrote:
                            > Rupert, Thanks for the idea but the pattern is one piece. Today after
                            > work I used a masonery bit to free the pattern out of the sand which
                            > looked a little like sandstone. I have another oil cooler pattern
                            > which has similar depth fins but not as many that I used as an
                            > experiment for the head castings. I am going to try a reduced amount
                            > of binder to see if that helps and less ramming of the sand. Usually
                            > deep fins need to be jolted, which I did, but I also rammed, so I'll
                            > try jolting. the learning continues....Part of the problem is me
                            > using Johnson paste wax as a release but it's hard to get it between
                            > all the fins which are about 1/4" apart and 2" deep. LL

                            --

                            yvt

                            Rupert Wenig
                            Camrose, Alberta, Canada.

                            email: rwenig2@...

                            http://users.xplornet.com/~rwenig/Home/
                          • Lyle
                            Not a bad idea Rupert. One of the main problems is getting the Johnson s wax between all the fins. Seems easy but there s bolt bosses and a spark plug boss
                            Message 13 of 15 , Oct 3, 2012
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                              Not a bad idea Rupert. One of the main problems is getting the Johnson's wax between all the fins. Seems easy but there's bolt bosses and a spark plug boss that's raised up between them so there's a lot of different reliefs going on. Heck, some of the problem could be my lack of patience which has nixed me before....
                              Thanks,
                              LL


                              --- In hobbicast@yahoogroups.com, Rupert <rwenig2@...> wrote:
                              >
                              > Hello Lyle,
                              > My words weren't clear and I assumed your using sodium silicate sand.
                              > Johnson's paste wax should work as long as you have complete coverage. I
                              > meant to fill the spaces between the fins with the SS sand, pack it only
                              > firmly (don't ram it). Rap the head on the side so the sand loosens a
                              > bit. Then, gas it to harden. I think the hardened mix should fall out.
                              > Do this for every space. Place them in place between the fins and make
                              > the complete mold again using SS sand as it should bind to the
                              > previously made fin cores. Only a firm packing is needed- don't ram it.
                              > Again, rap the head enough to loosen it before gassing. The head should
                              > fall out when you turn the flask over provided there are no undercuts to
                              > consider. Don't know if this will work with other types of resin set
                              > sands. But, I do think the SS sand should work.
                              >
                              > Rupert
                              >
                              > On 10/2/2012 9:27 PM, Lyle wrote:
                              > > Rupert, Thanks for the idea but the pattern is one piece. Today after
                              > > work I used a masonery bit to free the pattern out of the sand which
                              > > looked a little like sandstone. I have another oil cooler pattern
                              > > which has similar depth fins but not as many that I used as an
                              > > experiment for the head castings. I am going to try a reduced amount
                              > > of binder to see if that helps and less ramming of the sand. Usually
                              > > deep fins need to be jolted, which I did, but I also rammed, so I'll
                              > > try jolting. the learning continues....Part of the problem is me
                              > > using Johnson paste wax as a release but it's hard to get it between
                              > > all the fins which are about 1/4" apart and 2" deep. LL
                              >
                              > --
                              >
                              > yvt
                              >
                              > Rupert Wenig
                              > Camrose, Alberta, Canada.
                              >
                              > email: rwenig2@...
                              >
                              > http://users.xplornet.com/~rwenig/Home/
                              >
                            • Rupert
                              Hello Lyle, Did you try a spray something like this in lew of the paste wax? I ve used it
                              Message 14 of 15 , Oct 3, 2012
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                                Hello Lyle,
                                Did you try a spray something like this
                                <http://www.smooth-on.com/Release-Agents-for/c1123_1226/index.html> in
                                lew of the paste wax? I've used it on over shellac and RTV rubber but
                                haven't tried it on metal to make SS sand molds.

                                Rupert

                                On 10/3/2012 11:18 AM, Lyle wrote:
                                > Not a bad idea Rupert. One of the main problems is getting the Johnson's wax between all the fins. Seems easy but there's bolt bosses and a spark plug boss that's raised up between them so there's a lot of different reliefs going on. Heck, some of the problem could be my lack of patience which has nixed me before....
                                > Thanks,
                                > LL
                                >
                                >
                                > --- In hobbicast@yahoogroups.com, Rupert <rwenig2@...> wrote:
                                >>
                                >> Hello Lyle,
                                >> My words weren't clear and I assumed your using sodium silicate sand.
                                >> Johnson's paste wax should work as long as you have complete coverage. I
                                >> meant to fill the spaces between the fins with the SS sand, pack it only
                                >> firmly (don't ram it). Rap the head on the side so the sand loosens a
                                >> bit. Then, gas it to harden. I think the hardened mix should fall out.
                                >> Do this for every space. Place them in place between the fins and make
                                >> the complete mold again using SS sand as it should bind to the
                                >> previously made fin cores. Only a firm packing is needed- don't ram it.
                                >> Again, rap the head enough to loosen it before gassing. The head should
                                >> fall out when you turn the flask over provided there are no undercuts to
                                >> consider. Don't know if this will work with other types of resin set
                                >> sands. But, I do think the SS sand should work.
                                >>
                                >> Rupert
                                >>
                                >> On 10/2/2012 9:27 PM, Lyle wrote:
                                >>> Rupert, Thanks for the idea but the pattern is one piece. Today after
                                >>> work I used a masonery bit to free the pattern out of the sand which
                                >>> looked a little like sandstone. I have another oil cooler pattern
                                >>> which has similar depth fins but not as many that I used as an
                                >>> experiment for the head castings. I am going to try a reduced amount
                                >>> of binder to see if that helps and less ramming of the sand. Usually
                                >>> deep fins need to be jolted, which I did, but I also rammed, so I'll
                                >>> try jolting. the learning continues....Part of the problem is me
                                >>> using Johnson paste wax as a release but it's hard to get it between
                                >>> all the fins which are about 1/4" apart and 2" deep. LL
                                >>
                                >> --
                                >>
                                >> yvt
                                >>
                                >> Rupert Wenig
                                >> Camrose, Alberta, Canada.
                                >>
                                >> email: rwenig2@...
                                >>
                                >> http://users.xplornet.com/~rwenig/Home/
                                >>
                                >
                                >
                                >
                                >
                                > ------------------------------------
                                >
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                                yvt

                                Rupert Wenig
                                Camrose, Alberta, Canada.

                                email: rwenig2@...

                                http://users.xplornet.com/~rwenig/Home/
                              • Lyle
                                That s exactly what I used over the paste wax. By the way, smooth - on is absolutely the best stuff I ve ever used (for making rubber molds). I use the
                                Message 15 of 15 , Oct 3, 2012
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                                  That's exactly what I used over the paste wax. By the way, smooth - on is absolutely the best stuff I've ever used (for making rubber molds). I use the brushable silicone and like it better than the urethanes. The spray on release worked OK on my simpler wood oil cooler pattern but it was still a hard pull from the sand, it didn't work so well on the heads, if at all. I've got an idea that will work but it'll take some redoing of the pattern before I'm able to try it. That and I didn't rap the pattern prior to the sand setting up. The reason being is I didn't want to cause stress fractures in the sand between the fins. And I never rap anything that was made in SS sand so why resin sand? But I'm going to cast an oil cooler this weekend (far less sand to waste if it doesn't work) and rap the pattern before set up. In the meantime I'm modifying my pattern with some stronger inserts so they don't pull out of the pattern before it's released. It's a lot of work though turning them all out on my lathe and then threading them.
                                  LL


                                  --- In hobbicast@yahoogroups.com, Rupert <rwenig2@...> wrote:
                                  >
                                  > Hello Lyle,
                                  > Did you try a spray something like this
                                  > <http://www.smooth-on.com/Release-Agents-for/c1123_1226/index.html> in
                                  > lew of the paste wax? I've used it on over shellac and RTV rubber but
                                  > haven't tried it on metal to make SS sand molds.
                                  >
                                  > Rupert
                                  >
                                  > On 10/3/2012 11:18 AM, Lyle wrote:
                                  > > Not a bad idea Rupert. One of the main problems is getting the Johnson's wax between all the fins. Seems easy but there's bolt bosses and a spark plug boss that's raised up between them so there's a lot of different reliefs going on. Heck, some of the problem could be my lack of patience which has nixed me before....
                                  > > Thanks,
                                  > > LL
                                  > >
                                  > >
                                  > > --- In hobbicast@yahoogroups.com, Rupert <rwenig2@> wrote:
                                  > >>
                                  > >> Hello Lyle,
                                  > >> My words weren't clear and I assumed your using sodium silicate sand.
                                  > >> Johnson's paste wax should work as long as you have complete coverage. I
                                  > >> meant to fill the spaces between the fins with the SS sand, pack it only
                                  > >> firmly (don't ram it). Rap the head on the side so the sand loosens a
                                  > >> bit. Then, gas it to harden. I think the hardened mix should fall out.
                                  > >> Do this for every space. Place them in place between the fins and make
                                  > >> the complete mold again using SS sand as it should bind to the
                                  > >> previously made fin cores. Only a firm packing is needed- don't ram it.
                                  > >> Again, rap the head enough to loosen it before gassing. The head should
                                  > >> fall out when you turn the flask over provided there are no undercuts to
                                  > >> consider. Don't know if this will work with other types of resin set
                                  > >> sands. But, I do think the SS sand should work.
                                  > >>
                                  > >> Rupert
                                  > >>
                                  > >> On 10/2/2012 9:27 PM, Lyle wrote:
                                  > >>> Rupert, Thanks for the idea but the pattern is one piece. Today after
                                  > >>> work I used a masonery bit to free the pattern out of the sand which
                                  > >>> looked a little like sandstone. I have another oil cooler pattern
                                  > >>> which has similar depth fins but not as many that I used as an
                                  > >>> experiment for the head castings. I am going to try a reduced amount
                                  > >>> of binder to see if that helps and less ramming of the sand. Usually
                                  > >>> deep fins need to be jolted, which I did, but I also rammed, so I'll
                                  > >>> try jolting. the learning continues....Part of the problem is me
                                  > >>> using Johnson paste wax as a release but it's hard to get it between
                                  > >>> all the fins which are about 1/4" apart and 2" deep. LL
                                  > >>
                                  > >> --
                                  > >>
                                  > >> yvt
                                  > >>
                                  > >> Rupert Wenig
                                  > >> Camrose, Alberta, Canada.
                                  > >>
                                  > >> email: rwenig2@
                                  > >>
                                  > >> http://users.xplornet.com/~rwenig/Home/
                                  > >>
                                  > >
                                  > >
                                  > >
                                  > >
                                  > > ------------------------------------
                                  > >
                                  > > 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
                                  > >
                                  > >
                                  > >
                                  > >
                                  > >
                                  > > -----
                                  > > No virus found in this message.
                                  > > Checked by AVG - www.avg.com
                                  > > Version: 2013.0.2677 / Virus Database: 2591/5802 - Release Date: 10/01/12
                                  > >
                                  > >
                                  >
                                  > --
                                  >
                                  > yvt
                                  >
                                  > Rupert Wenig
                                  > Camrose, Alberta, Canada.
                                  >
                                  > email: rwenig2@...
                                  >
                                  > http://users.xplornet.com/~rwenig/Home/
                                  >
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