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  • the_nemecs
    Hello, I ve been casting urethane suspension bushings for a certain type of classic car for a few of years as a hobby. As the demand for these grows, so does
    Message 1 of 48 , Dec 30 10:52 AM
      Hello,

      I've been casting urethane suspension bushings for a certain type of classic
      car for a few of years as a hobby. As the demand for these grows, so does my
      need to become more professional, and I'm looking for ways to increase the
      quality of my products, so I'm thrilled to have found this group!



      Most of what I know about the casting and mold making process I have learned
      from either trial & error or from videos I found on the Tap Plastics
      website. I have used both of the Tap Plastics Regular Silicone RTV, and more
      recently their Platinum Silicone systems. Some of my first generation molds
      built from the regular RTV Silicone are starting to get hard and are
      developing hairline fractures that are starting to be represented in the
      cast pieces, so it's time to start rebuilding some of these molds.



      I have been most impressed with the Tap Platinum Silicone for most things,
      however, unfortunately it reacts with vulcanized rubber during the mold
      making process. So my first question to the group is, do any of you know of
      a good way to protect the silicone compound from the rubber during the mold
      making process? I have tried coating the pieces with a mold release spray
      with no luck.



      Also, when trying to make a 2-part mold, How do you keep the silicone from
      sticking to itself? I tried mold release spray but that didn't work.



      Thank you in advance & I hope to learn a lot from this group.



      Sincerely,

      Jesse Nemec



      [Non-text portions of this message have been removed]
    • Corey Minion
      Another point to make is that vulcanized molds are notoriously loaded with sulfur. Sulfur is the plat rtv kryptonite. Corey Minion MinionsWeb.com
      Message 48 of 48 , Jan 2, 2012
        Another point to make is that vulcanized molds are notoriously loaded with
        sulfur.
        Sulfur is the plat rtv kryptonite.


        Corey Minion
        MinionsWeb.com
        Http://www.minionsweb.com/osStore
        Sent via Droid

        -----Original message-----
        From: Ted Quick <rim_molder@...>
        To: "casting@yahoogroups.com" <casting@yahoogroups.com>
        Sent: Mon, Jan 2, 2012 04:57:38 GMT+00:00
        Subject: Re: [casting] New Member

        Jesse,

        The problem with Platinum catalyzed RTV is that it wont react where it
        touches anything containing sulfur, and you're tight mold release won't
        protect it. It MIHT be possible to seal the original with laquer or shellac,
        but that probably won't work with a rubber original because of it's
        flexibility and poor adhesion with any coating.

        You should be able to cast a good mold with the Regular RTV, which is Tin
        catalyzed since it doesn't have the same problem as the Platinum variety
        has. Of course that has a shorter lifetime and will harden & crack a lot
        sooner.

        As for mold release used between 2 silicone mold halves you need to choose
        carefully, and ask if a mold release will keep silicone mold halves
        separate. A good mold release that I heard of here is Price-Driscoll Ultra
        4, look on: http://www.price-driscoll.com/formulations.html

        Call them at 800-442-3575, they will be glad to answer any questions you
        have.

        Ted Quick




        >________________________________
        > From: the_nemecs <the_nemecs@...>
        >To: casting@yahoogroups.com
        >Sent: Friday, December 30, 2011 1:52 PM
        >Subject: [casting] New Member
        >
        >Hello,
        >
        >I've been casting urethane suspension bushings for a certain type of
        classic
        >car for a few of years as a hobby. As the demand for these grows, so does
        my
        >need to become more professional, and I'm looking for ways to increase the
        >quality of my products, so I'm thrilled to have found this group!
        >
        >
        >
        >Most of what I know about the casting and mold making process I have
        learned
        >from either trial & error or from videos I found on the Tap Plastics
        >website. I have used both of the Tap Plastics Regular Silicone RTV, and
        more
        >recently their Platinum Silicone systems. Some of my first generation molds
        >built from the regular RTV Silicone are starting to get hard and are
        >developing hairline fractures that are starting to be represented in the
        >cast pieces, so it's time to start rebuilding some of these molds.
        >
        >
        >
        >I have been most impressed with the Tap Platinum Silicone for most things,
        >however, unfortunately it reacts with vulcanized rubber during the mold
        >making process. So my first question to the group is, do any of you know of
        >a good way to protect the silicone compound from the rubber during the mold
        >making process? I have tried coating the pieces with a mold release spray
        >with no luck.
        >
        >
        >
        >Also, when trying to make a 2-part mold, How do you keep the silicone from
        >sticking to itself? I tried mold release spray but that didn't work.
        >
        >
        >
        >Thank you in advance & I hope to learn a lot from this group.
        >
        >
        >
        >Sincerely,
        >
        >Jesse Nemec
        >
        >
        >
        >[Non-text portions of this message have been removed]
        >
        >
        >
        >------------------------------------
        >
        >Yahoo! Groups Links
        >
        >
        >
        >
        >
        >

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





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