Loading ...
Sorry, an error occurred while loading the content.
 

Re: materials question

Expand Messages
  • wogelin
    Hello, this is an intersting subject, I am just thinking about to buying a vulanizer (like Romanoff´s table top model). Problem is I want to do the casting in
    Message 1 of 13 , Mar 1, 2005
      Hello,
      this is an intersting subject, I am just thinking about to buying a
      vulanizer (like Romanoff´s table top model). Problem is I want to do
      the casting in PU Resin not pewter or any other metal. The given
      platen-size of the vulcanizer seems just good enough for my purposes.
      My question is, has anybody tried casting pu-resin in vulcanized
      rubber-molds?? I cant´t find any info on "heatvulcanzing-resin-
      friendly-rubber" Thanks for your help
      Wolfgang
    • Ted Quick
      Try looking at: http://www.tekcast.com/casting.htm#TEKPLASTIC%20LIQUID%20THERMOSET%20PLASTICS They have information about spincasting resins in many places on
      Message 2 of 13 , Mar 1, 2005
        Try looking at:

        http://www.tekcast.com/casting.htm#TEKPLASTIC%20LIQUID%20THERMOSET%20PLASTICS

        They have information about spincasting resins in many places on their site.

        Ted Quick
        --- wogelin <w.g@...> wrote:

        >
        > Hello,
        > this is an intersting subject, I am just thinking about to buying a
        > vulanizer (like Romanoff�s table top model). Problem is I want to do
        > the casting in PU Resin not pewter or any other metal. The given
        > platen-size of the vulcanizer seems just good enough for my purposes.
        > My question is, has anybody tried casting pu-resin in vulcanized
        > rubber-molds?? I cant�t find any info on "heatvulcanzing-resin-
        > friendly-rubber" Thanks for your help
        > Wolfgang
        >
        >
        >
        >
        >


        =====
        Ted Quick
      • Terry Wellman
        Hi Wolfgang, We spin resin in vulcanized molds on a regular basis. Despite the learning curve, it is entirely do-able. The main concern is the quality,
        Message 3 of 13 , Mar 1, 2005
          Hi Wolfgang,

          We spin resin in vulcanized molds on a regular basis. Despite the learning
          curve, it is entirely do-able. The main concern is the quality, condition,
          and geometry of the prototypes that you wish to reproduce.

          We have used several brands of rubber and silicone disc sets before settling
          on Chardan Ltd. of Attleboro, MA for our organic rubber discs. They have
          several black organic rubbers that work well. I like their 100, 145, and 180
          series organics. I am awaiting a sample of their 300 series to try out this
          week. It is a softer more supple rubber that works well with high detail
          prototypes. I'll let you know how it works on the parts that I want to try
          it with. Chardan's number is 1-508-226-2708. Charles Katsanos is the owner
          and Lee is his sales rep. Good people to deal with.

          We tried the Millenium brand of silicone discs with some success. They're ok
          but I like the Romanoff Silcast silicone discsets better. The Milleniums
          seem to have a sweet odor that tends to permeate the shop. Yecch! ;-) The
          Red Silcast works well.

          At some point we'll try the Nicem line of silicone discs. I like to try
          different products in order to stay on top of things and find the best
          materials to handle our requirments. Once we find something good, we tend to
          stick with it. Contenti Company carries Nicem. 1-800-343-3364.

          We vulcanize 9" and 12" molds in several different frames. I believe that
          our current frames are 1", 2", and 4" for 12" discsets along with 1", and 2"
          for 9" discsets. Normally we vulcanize between 310 and 320 degrees F for 60
          minutes. I usually preheat the frames before dropping the discs in.

          We also make spin molds with RTV too for more difficult and fragile parts.
          The issue here is labor as you now have to clay in the parts, make sure that
          you've got clean parting lines, registration nuts, pour, wait 8-12 hours,
          flip it over, clean out the clay, spray with Parfilm 4 as a protective
          barrier coat then pour the second part of the mold, wait yet another 8-12
          hours, pry open, demold the masters, spray both halves with Parfilm 4 again,
          heat up the halves, then spin. Of course this is the simplified version.;-)

          Typically we're spinning them between 75-450 RPM, 80 PSI, 5 minute cycles
          with two minute post cure settings on the spinner. For resin, we're spinning
          with Alumilite's RC-3. It mixes very well and pours like cream into the
          spinner. With a 3-5 minute gel time, it works very well for us in this
          application. There are other resins out there to spin with. This is our
          preference. Be careful spinning filled resins. One company advertises
          aluminum filled resin for spinning. As this is a centrifugal operation, any
          filler is likely to find its way to the outer edges of the mold cavities
          while leaving the inner edges to just resin. There is a misnomer out there
          about spinning with fillers. Yes, it can be done but you need to spin at a
          slower RPM. You might find that you need higher RPM to completely fill your
          cavities depending upon their geometries of course.

          When spinning resin, you won't need the pour funnel on the top of your
          machine as you don't need to worry about aiming the metal into the center
          gate. Resin pours pretty straight into the machine.

          One issue to keep in mind is the pressure level on the spinner. You want to
          insure that you have enough pressure to keep the two mold halves sealed in
          order to reduce the chance of resin spraying our of the seam onto the wall
          of the spin caster. Ask me how I know this! ;-) We have had times where we
          didn't have enough pressure on a mold during its first cycles and could hear
          the resin hitting the wall of the tub. It's like a short but heavy
          rainstorm. ;-)

          Hope this helps,
          Terry
        • Wolfgang Gebranzig
          Hi Terry and Ted Thank you very very much for your detailed answer. Really a fantastic info and help to me. It is not the quality of the various RTV-Rubber´s
          Message 4 of 13 , Mar 2, 2005
            Hi Terry and Ted

            Thank you very very much for your detailed answer. Really a fantastic info
            and help to me. It is not the quality of the various RTV-Rubber´s that
            gives me problems, but the amount of work involved creating such molds
            combined with the constant fear of poor results due to "underbleeding" or
            poor fit of the resulting mold parts.
            I wish to produce 54 mm and 70 mm figurines for a special collector´s
            market. Nothing unusal but I have to cast the figures in "one piece" not
            like the available multi-part resin model kits of figurines. I am aiming for
            a injection cast look of my figurines just like the soft plastic products of
            various makers on the toy market.
            I finally solved the beginner´s problems of pressure- and vacuum-casting as
            well as mold design. Promising results so far but the RTV-molds still do not
            really suit my needs. I also tried blockmolds which I cut to create the two
            mold halfs, tried clear RTV for that as well but given the amount of work
            and the prices of various rubbers - it still does not give me the results I
            am searching for. I do not spincast my molds. My "masterplan" would look
            like this: Creating a square mold of a master figurine in the vulcanisr (a
            table model like Romanoff´s since working space is a issue as well) than
            cast 6-10 copies, leaving the venting sprues etc. intact and do another mold
            of those figures which will hold 6-10 figurines. Thus resulting in a
            economic and affordable "mass-production-mold(s)".
            I will give another variant a try this week. I constructed a wooden mold
            frame , top plates made of steel and a simple hydraulic press. I will try
            and use some kneadable dental rubber on this project trying to simulate the
            vulcanising effect. I will "sandwich" the master between two talc dusted
            portions of the rubber inside the wooden frame, put the steel plates on
            bottom and top of the mold frame and apply pressure, I drilled small hole
            into the wood frame to evacuate surplus rubber from the mold . So far for
            the theory, no idea if it will work and how the rubber will react with the
            resin but I will give it a try .
            Thank you for your help
            Best regards
            Wolfgang

            -----Ursprüngliche Nachricht-----
            Von: Terry Wellman [mailto:mwhirailer@...]
            Gesendet: Mittwoch, 2. März 2005 07:22
            An: casting@yahoogroups.com
            Betreff: Re: [casting] Re: materials question

            Hi Wolfgang,

            We spin resin in vulcanized molds on a regular basis. Despite the learning
            curve, it is entirely do-able. The main concern is the quality, condition,
            and geometry of the prototypes that you wish to reproduce.

            We have used several brands of rubber and silicone disc sets before settling
            on Chardan Ltd. of Attleboro, MA for our organic rubber discs. They have
            several black organic rubbers that work well. I like their 100, 145, and 180
            series organics. I am awaiting a sample of their 300 series to try out this
            week. It is a softer more supple rubber that works well with high detail
            prototypes. I'll let you know how it works on the parts that I want to try
            it with. Chardan's number is 1-508-226-2708. Charles Katsanos is the owner
            and Lee is his sales rep. Good people to deal with.

            We tried the Millenium brand of silicone discs with some success. They're ok
            but I like the Romanoff Silcast silicone discsets better. The Milleniums
            seem to have a sweet odor that tends to permeate the shop. Yecch! ;-) The
            Red Silcast works well.

            At some point we'll try the Nicem line of silicone discs. I like to try
            different products in order to stay on top of things and find the best
            materials to handle our requirments. Once we find something good, we tend to
            stick with it. Contenti Company carries Nicem. 1-800-343-3364.

            We vulcanize 9" and 12" molds in several different frames. I believe that
            our current frames are 1", 2", and 4" for 12" discsets along with 1", and 2"
            for 9" discsets. Normally we vulcanize between 310 and 320 degrees F for 60
            minutes. I usually preheat the frames before dropping the discs in.

            We also make spin molds with RTV too for more difficult and fragile parts.
            The issue here is labor as you now have to clay in the parts, make sure that
            you've got clean parting lines, registration nuts, pour, wait 8-12 hours,
            flip it over, clean out the clay, spray with Parfilm 4 as a protective
            barrier coat then pour the second part of the mold, wait yet another 8-12
            hours, pry open, demold the masters, spray both halves with Parfilm 4 again,
            heat up the halves, then spin. Of course this is the simplified version.;-)

            Typically we're spinning them between 75-450 RPM, 80 PSI, 5 minute cycles
            with two minute post cure settings on the spinner. For resin, we're spinning
            with Alumilite's RC-3. It mixes very well and pours like cream into the
            spinner. With a 3-5 minute gel time, it works very well for us in this
            application. There are other resins out there to spin with. This is our
            preference. Be careful spinning filled resins. One company advertises
            aluminum filled resin for spinning. As this is a centrifugal operation, any
            filler is likely to find its way to the outer edges of the mold cavities
            while leaving the inner edges to just resin. There is a misnomer out there
            about spinning with fillers. Yes, it can be done but you need to spin at a
            slower RPM. You might find that you need higher RPM to completely fill your
            cavities depending upon their geometries of course.

            When spinning resin, you won't need the pour funnel on the top of your
            machine as you don't need to worry about aiming the metal into the center
            gate. Resin pours pretty straight into the machine.

            One issue to keep in mind is the pressure level on the spinner. You want to
            insure that you have enough pressure to keep the two mold halves sealed in
            order to reduce the chance of resin spraying our of the seam onto the wall
            of the spin caster. Ask me how I know this! ;-) We have had times where we
            didn't have enough pressure on a mold during its first cycles and could hear
            the resin hitting the wall of the tub. It's like a short but heavy
            rainstorm. ;-)

            Hope this helps,
            Terry





            Yahoo! Groups Sponsor
            ADVERTISEMENT
            click here
            <http://us.ard.yahoo.com/SIG=129opih5h/M=298184.6018725.7038619.3001176/D=gr
            oups/S=1705063511:HM/EXP=1109830952/A=2593423/R=0/SIG=11el9gslf/*http://www.
            netflix.com/Default?mqso=60190075>


            _____

            Yahoo! Groups Links
            * To visit your group on the web, go to:
            http://groups.yahoo.com/group/casting/
            <http://groups.yahoo.com/group/casting/>

            * To unsubscribe from this group, send an email to:
            casting-unsubscribe@yahoogroups.com
            <mailto:casting-unsubscribe@yahoogroups.com?subject=Unsubscribe>

            * Your use of Yahoo! Groups is subject to the Yahoo! Terms of
            Service <http://docs.yahoo.com/info/terms/> .


            [Non-text portions of this message have been removed]
          Your message has been successfully submitted and would be delivered to recipients shortly.