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42215Re: [hobbicast] Re: Spray type mold release?

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  • Rupert
    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/
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