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Re: Hypertufa (aka hyper-tuffa)

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  • RT
    ... the density at 50 pcf +/- 25%. ... Thanks for that MeatHook. The +/- 25% is interesting, especially the possibility of -25%. I was thinking that it might
    Message 1 of 5 , Mar 1, 2006
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      --- In SB-r-us@yahoogroups.com, Norbert Senf <mheat@...> wrote:
      >
      > At 04:06 PM 2/28/2006 -0500, Rob Tom wrote:
      > >Has anyone here made items out of hypertufa ?
      > >(Sand + Portland cement + peat moss)
      > >(snip)
      >
      > Hi Rob: I've only fooled with it on a very limited scale. I'd guess
      the density at 50 pcf +/- 25%.
      >
      > Not all that much different from vermiculite/portland,

      Thanks for that MeatHook.

      The +/- 25% is interesting, especially the possibility of -25%.

      I was thinking that it might be necessary to use a lightweight
      aggregate in place of sand if further lightening were desired but at a
      mere (possible) 25 pcf, it wouldn't be.


      From the bits I've been able to find on-line about hypertufa, I get
      the impression that the strength of the material increases with the
      increase of the peat portion in the mix .

      (ie more peat = less sand = stronger material = lighter material)

      Would that impression be accurate ? (Seems too good to be true)
    • RT
      ... -25% of 50 pcf, you dodo. Not 25 pcf. Geeze. Some people s kids. Eh ? Sorry about that MeatHook.
      Message 2 of 5 , Mar 1, 2006
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        --- In SB-r-us@yahoogroups.com, some arithmetically-challenged dodo
        wrote:

        > The +/- 25% is interesting, especially the possibility of -25%.

        > at a mere (possible) 25 pcf, [further lightening] wouldn't be.

        -25% of 50 pcf, you dodo.
        Not 25 pcf.
        Geeze. Some people's kids. Eh ?
        Sorry about that MeatHook.
      • Norbert Senf
        ... Don t know, I ve never done any tests with it. I d guess if the peat actually has fibrous qualities, it could add some tensile strength. I wouldn t think
        Message 3 of 5 , Mar 1, 2006
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          At 11:16 PM 3/1/2006 +0000, RT wrote:
          >(snip)
          >
          > From the bits I've been able to find on-line about hypertufa, I get
          >the impression that the strength of the material increases with the
          >increase of the peat portion in the mix .
          >
          >(ie more peat = less sand = stronger material = lighter material)
          >
          >Would that impression be accurate ? (Seems too good to be true)

          Don't know, I've never done any tests with it.

          I'd guess if the peat actually has fibrous qualities, it could add some
          tensile strength. I wouldn't think that you'd be gaining much from the
          sand.

          We cast a fair number of vermiculite concrete
          slab pieces, and have used different types
          ("concrete aggregate" ,"plaster aggregate",
          "block and cavity fill"), mainly based on
          availability. We tried adding sand but it just
          made the pieces heavier. The mixing method
          has a big effect, as a lot of shear will break
          down the aggregate. Peat moss might behave
          in a similar fashion.

          Like a lot of the other non-standard materials
          like clay and lime plasters, I don't
          think you can avoid making a number of test mixes
          and adjusting as you go to get the
          properties that you want / avoid the properties
          you don't want. There are more than a few
          scrap slabs in our landfill from when materials
          changed, shop person changed, etc.

          We have to be pretty rigorous about documenting
          successful procedures, as reinventing everything from scratch
          would be a big job, and it makes it much easier
          to train a new person, or refresh somebody
          who hasn't done it for awhile.

          ----------------------------------------
          Norbert Senf---------- mheat(at)mha-net.org
          Masonry Stove Builders
          RR 5, Shawville------- www.heatkit.com
          Qu├ębec J0X 2Y0-------- fax:-----819.647.6082
          ---------------------- voice:---819.647.5092
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