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Re: [bolger] Micro Progress/lead hardness

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  • Sakari Aaltonen
    ... Which chart did you check? I checked the ones in Steward s Boatbuilding Manual and Gerr s The Nature of Boats . Both show stainless steel in *two*
    Message 1 of 19 , May 1, 2000
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      David Jost wrote:

      > I just checked the chart of metals/galvanic corrosion index. I will
      > stay with Stainless steel threaded rod instead of the bronze as
      > planned. too bad, I have a garage full of old bronze rod from a
      > neighbor that used to make the stuff at a foundry in Connecticut.
      > These bronze rods are at least 50 years old and were used to hold up
      > garden fencing at an oceanside garden in Harwich. They are still as
      > good as new after 50 years of horrendous salt encrusted air. The
      > table says that lead and bronze are not as compatible as stainless
      > and
      > lead. I hope that I can find 316 type stainless available.

      Which chart did you check? I checked the ones in Steward's
      "Boatbuilding Manual" and Gerr's "The Nature of Boats".
      Both show stainless steel in *two* places. This comes about
      because stainless steel has two states, active and passive.
      If it is in (steady) contact with oxygen (air or water), its
      state is passive and it is more compatible with lead than
      bronze. However, if there is no oxygen, like inside a keel,
      then stainless steel becomes active, and is much less compatible
      than bronze. That is, it will corrode (the keel lead will
      eat it, so to speak). This applies to type 316, too.


      Sakari Aaltonen
    • David Jost
      That certainly explains a lot! I will stick with bronze rod (since I already have quite a bit of it). I certainly can see why stainless would corrode under
      Message 2 of 19 , May 2, 2000
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        That certainly explains a lot! I will stick with bronze rod (since I
        already have quite a bit of it). I certainly can see why stainless
        would corrode under such circumstances. I would rather have the
        ballast corrode than the fastenings. I had an old Herreshoff day
        sailor that had bronze fastenings throughout. They were still in
        excellent condition despite 30 years of immersion in salt water. The
        keel on that boat was starting to corrode a bit, mainly due to the
        interaction of the copper bottom paint with the lead. This was
        shortly
        after the ban on paints with TFB in them. (I think that's the
        correct
        name)

        I now understand how stainless cannot be effective in an anaerobic
        environment. It needs to be exposed to the air to form its
        protective
        coating.

        Thanks for the input.
        David Jost
      • Bernie Wolfard
        I think the idea of dabbling in traditional boat building methods is the only valid reason for bolting a MICRO keel. There is a huge downside to this in that
        Message 3 of 19 , May 2, 2000
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          I think the idea of dabbling in "traditional" boat building
          methods
          is the only valid reason for bolting a MICRO keel. There is a huge
          downside to this in that it is generally considered a bad idea to
          drill holes in the bottom of a boat!
          As designed, a MICRO keel will pull the bottom off the boat before it
          lets go. This has been proved in personal experience as well in
          countless numbers of MICRO'S out there with keels attached as per
          plans. MICRO'S keel structure is a true composite, only different
          from high tech airplanes in that the composites interior foam is
          replaced with lead. It is as strong or stronger but with the mass
          make it a keel instead of a wing.
          That said, the idea of using ½" plywood on MICRO'S bottom is
          well
          founded. She will not be worst for the weight and be much strong,
          especially in taking the ground.

          --- In bolger@egroups.com, "David Jost" <djost@m...> wrote:
          > Peter,
          > I do not think that this is so much being pre-occupied, as
          being
          > careful. I think you have the correct idea in through bolting the
          > keel and building it vertical. I can see only good things
          happening
          > for what amount to very little extra expense here. I will install
          3
          > bronze keel bolts that will run the length of the mold, and will
          > provied recesses for the external nuts. I think that the wood
          dowels
          > were a great idea! I think I will also continue to use the exterior
          > sheething as well since I already have the material on hand.
          > How did you back up the nuts on the interior? And, What did
          you
          > use for caulking around the bolt holes?
          >
          > David Jost
          > " glorious in Boston today, "Firefly" now has two sides, 2
          frames,
          > and all spars and sails."
        • peter lenihan
          Hi Bernie, The huge downside which you refer to,is ONLY true if one forgets to plug/fill the holes one has drilled with something useful! :-D Warm Regards,
          Message 4 of 19 , May 2, 2000
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            Hi Bernie,
            The"huge downside"which you refer to,is ONLY true if one forgets
            to plug/fill the holes one has drilled with something useful! :-D
            Warm Regards,

            Peter Lenihan,itching to begin his seventh season with his MICRO
            which looks as beautiful and strong as the day she was launched,off
            the shores of the St.Lawrence......316 stainless keelbolts and
            all.....




            --- In bolger@egroups.com, "Bernie Wolfard" <berniew@n...> wrote:
            > I think the idea of dabbling in "traditional" boat building
            > methods
            > is the only valid reason for bolting a MICRO keel. There is a huge
            > downside to this in that it is generally considered a bad idea to
            > drill holes in the bottom of a boat!
            > As designed, a MICRO keel will pull the bottom off the boat before
            it
            > lets go. This has been proved in personal experience as well in
            > countless numbers of MICRO'S out there with keels attached as per
            > plans. MICRO'S keel structure is a true composite, only different
            > from high tech airplanes in that the composites interior foam is
            > replaced with lead. It is as strong or stronger but with the mass
            > make it a keel instead of a wing.
            > That said, the idea of using ½" plywood on MICRO'S bottom is
            > well
            > founded. She will not be worst for the weight and be much strong,
            > especially in taking the ground.
            >
            > --- In bolger@egroups.com, "David Jost" <djost@m...> wrote:
            > > Peter,
            > > I do not think that this is so much being pre-occupied, as
            > being
            > > careful. I think you have the correct idea in through bolting the
            > > keel and building it vertical. I can see only good things
            > happening
            > > for what amount to very little extra expense here. I will install
            > 3
            > > bronze keel bolts that will run the length of the mold, and will
            > > provied recesses for the external nuts. I think that the wood
            > dowels
            > > were a great idea! I think I will also continue to use the
            exterior
            > > sheething as well since I already have the material on hand.
            > > How did you back up the nuts on the interior? And, What did
            > you
            > > use for caulking around the bolt holes?
            > >
            > > David Jost
            > > " glorious in Boston today, "Firefly" now has two sides, 2
            > frames,
            > > and all spars and sails."
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