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Re: [Michalak] Re: Advice on bottom thickness of piccup pram

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  • Martin Houston
    I ve never seen Sureply but I checked out Ultraply at Menards & didn t like it. Seemed to have thick inner core & very thin veneers on either side. I know many
    Message 1 of 22 , Jun 5, 2012
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      I've never seen Sureply but I checked out Ultraply at Menards & didn't like it. Seemed to have thick inner core & very thin veneers on either side. I know many good boats have been built from it but I used premium ACX. 3 equal thickness layers. Strong & takes screws & glue well.



      ________________________________
      From: gary <gbship@...>
      To: Michalak@yahoogroups.com
      Sent: Tuesday, June 5, 2012 7:05 PM
      Subject: [Michalak] Re: Advice on bottom thickness of piccup pram



       

      Mike:
      Got tied up and haven't been able to follow the thread for a couple days. And naturally have a couple more thoughts.
      -- the difference between 6 mm ply and 5.2 mm ply on a boat the size of a Piccup is immaterial. Even if you weren't planning to glass both the inside and outside bottom, it wouldn't matter. In any case, since you're planning to glass both sides of the bottom for abrasion resistance, you'll be adding several times the strength than is lost from a 0.8 mm reduction in thickness.
      -- Unless you're planning on cartopping the boat, I think the slight extra weight of glassing the bottom is well worth it for the reduced maintenance you'll have. Also, I don't think it's a particularly good boat to cartop, being a bit above the ideal weight and being too short to load easily (you can't put one end on the ground and lift the other to the top of the vehicle).
      -- If you haven't made the leeboard yet, I'd follow some advice Michalak gave a while ago and make it wider than the drawings show. My plans had a tapered board from 7 to 9 inches wide, if memory serves. I did another one adding 3 inches to the front edge, which still fits the designed upper and lower leeboard guards and the boat is much closer winded and maneuvers better.

      I wouldn't use Sureply as I think the stuff Mike Monies used delaminated.

      Gary

      --- In Michalak@yahoogroups.com, "Mike" <rudder59@...> wrote:
      >
      >
      > Nels,
      > I couldn't agree more. The response and suggestions have been tremendous and provided insight into the pros and cons of different methods that I wouldn't have had access to on my own.
      > I think anders strategy for doing the cloth first then the tape is a perfect example of gaining insight from other peoples experiences.
      >
      > I originally went to box store for Ultraply but when I got there they had switched to carrying Sureply. Another example of why you need to follow your own internal compass and not be taken off course by someone else's agenda
      >
      > I appreciate all the feedback and hope I can contribute to others questions as we go along.
      > Thanks again to everyone.
      >
      > Regards,
      > Mike
      > --- In Michalak@yahoogroups.com, "prairiedog2332" <nelsarv@> wrote:
      > >
      > >
      > > Great to hear the feedback on this discussion. I think it will all be
      > > very useful for perspective builders.
      > >
      > > Some added thoughts and observations;
      > >
      > > 1. I think in a multichine hull like the piccup pram I like what Anders
      > > wrote.
      > >
      > > 2. In a bigger hull like the Light Schooner I would go with thicker
      > > plywood. 3/8" MDO would be my choice.
      > >
      > > 3. It would be easier to go with heavier glass on the bottom than adding
      > > another layer of plywood. Say 10 oz instead of 6?
      > >
      > > 4. Glassing the interior would add strength but a lot of extra work.
      > > Thicker plywood also adds flotation but glass adds extra weight.
      > >
      > > 5. On a single chine boat you already have abrasion resistance if the
      > > chine logs are on the outside which Jim Michalak seems to suggest works
      > > better than interior chine logs. But even then he suggests some tape
      > > over the chine logs.
      > >
      > > 6. Mike Monies has chosen to no longer use Sureply but only Occume. But
      > > he builds boats for others on consignement from what I understand. I
      > > agree that is the better choice if one can afford it.
      > >
      > > Nels
      > >
      > >
      > >
      > >
      > >
      > >
      > >
      > >
      > >
      > >
      > >
      > >
      > > --- In Michalak@yahoogroups.com, Martin Houston <mtnridr13@> wrote:
      > > >
      > > > Glass surly does add weight, but it also adds streangth. I tend to be
      > > hard on equipment, if it is weak I will break it. I plan to glass my AF3
      > > inside & out. I believe It will be strong & watertight. It is big enough
      > > to handle the extra weight, it won't be that much. Extra thickness in
      > > ply would add streangth without needing extra glass & is probably the
      > > way to go. My boats tend to be heavy & strong but I don't car top them.
      > > So far none has broke.
      > > >
      > > >
      > > >
      > > > ________________________________
      > > > From: Mike rudder59@
      > > > To: Michalak@yahoogroups.com
      > > > Sent: Sunday, June 3, 2012 7:17 PM
      > > > Subject: [Michalak] Re: Advice on bottom thickness of piccup pram
      > > >
      > > >
      > > >
      > > > Â
      > > >
      > > > I checked the patriot web site -maker of the Sureply - and the Sureply
      > > underlayment thickness is 5.2 -5.5 mm. I chose it because it is
      > > guaranteed not to have any voids in it, has good glue qualities etc.
      > > > I plan on fiberglassing the bottom up to about six inches up the side
      > > panels. May think about taking it all the way up the sides based on
      > > concerns that everyone has expressed.
      > > >
      > > > Plan on fiberglassing inside portion between bulkheads A&C where you
      > > sit and most wear and tear will occur. Wondering if I should also glass
      > > the inside portion of the bottom in the front and rear compartments for
      > > strength or if I only need to be concerned about the open area.
      > > >
      > > > Thanks everyone for the feedback and suggestions.
      > > >
      > > > Mike
      > > >
      > > > --- In Michalak@yahoogroups.com, David Calloway david@ wrote:
      > > > >
      > > > > An inch is 25.4 mm, making 6mm ply a 1/4 inch. I'd feel safe with
      > > 5mm
      > > > > glassed both sides, just my 2 cents,
      > > > >
      > > > > dave
      > > > >
      > > > > On Sun, Jun 3, 2012 at 5:36 PM, Martin Houston mtnridr13@ wrote:
      > > > >
      > > > > > **
      > > > > >
      > > > > >
      > > > > > Or glass the heck out of it, both sides.
      > > > > >
      > > > > > ________________________________
      > > > > > From: Scot McPherson scot.mcpherson@
      > > > > > To: "Michalak@yahoogroups.com" Michalak@yahoogroups.com
      > > > > > Sent: Sunday, June 3, 2012 5:48 PM
      > > > > > Subject: Re: [Michalak] Re: Advice on bottom thickness of piccup
      > > pram
      > > > > >
      > > > > >
      > > > > >
      > > > > >
      > > > > >
      > > > > > Dude, that's not slightly thinner...that's a ALOT thinner. 4mm is
      > > just a
      > > > > > touch over 1/8th inch. I inch is approximately 30mm. 30 / 4 = 7.5,
      > > > > > therefore 7.5 mm = approximate 1/4 inch. 4mm is just over half
      > > that. I
      > > > > > would either scratch using that, or double up on every panel. That
      > > boat may
      > > > > > crumple under load.
      > > > > >
      > > > > > Scot McPherson, PMP CISSP MCSA
      > > > > > Old Lyme, CT
      > > > > > Le Claire, IA
      > > > > > http://www.linkedin.com/in/scotmcpherson
      > > > > > Sent from my iPhone
      > > > > >
      > > > > > On Jun 3, 2012, at 12:03 PM, "Mike" rudder59@ wrote:
      > > > > >
      > > > > > > David,
      > > > > > > Thank you. JM 's plans call for 1/4 " plywood . Sureply is
      > > slightly
      > > > > > thinner then that (4mm) so wanted to be sure I wasn't creating a
      > > problem
      > > > > > with it.
      > > > > > > Mike
      > > > > > >
      > > > > > > --- In Michalak@yahoogroups.com, "D.G. Cassidy" <d.cassidy@>
      > > wrote:
      > > > > > > >
      > > > > > > > What does JM call for in the plans?
      > > > > > > > I would suggest doing whatever the plans specify.
      > > > > > > > This is one of JM's most popular designs; if the was a problem
      > > with
      > > > > > bottom thickness, he would have corrected the plans long ago.
      > > > > > > >
      > > > > > > > Adding extra weight will not necessarily make the boat any
      > > safer
      > > > > > (though it will make it harder to get on the roof of a car). That
      > > being
      > > > > > said, a protective layer of fiberglas on the bottom is a good idea
      > > of you
      > > > > > are going to be doing a lot of beaching, using concrete ramps,
      > > etc. (6 oz.
      > > > > > cloth is sufficient for this purpose).
      > > > > > > >
      > > > > > > > Holding weight is usually not the problem with thin bottoms.
      > > It is
      > > > > > puncture resistance. If it is something that keeps you awake at
      > > nights,
      > > > > > simply do not walk around in the boat when it is out of water and
      > > you
      > > > > > should never see a problem (a good idea with any plywood boat).
      > > > > > > >
      > > > > > > > David C
      > > > > > > >
      > > > > > > > On Jun 3, 2012, at 9:58 AM, Mike wrote:
      > > > > > > >
      > > > > > > > > Got sidetracked on my build of piccup pram by some health
      > > issues but
      > > > > > getting back on track now and should finish tie wraps of panels so
      > > I can do
      > > > > > the fillets on inside seams by next week. I've used Sureply
      > > plywood
      > > > > > underlayment (4 pr 5 mm thickness).
      > > > > > > > >
      > > > > > > > > I would appreciate any advice regarding the bottom thickness
      > > in the
      > > > > > area that you sit in. I thought about doubling up the thickness by
      > > just
      > > > > > putting in another a layer of the sure ply in that area since it
      > > will get
      > > > > > the most abuse or possibly just putting a layer of fiberglass
      > > cloth and
      > > > > > resin on that open area.
      > > > > > > > >
      > > > > > > > >
      > > > > > > >
      > > > > > > >
      > > > > > > >
      > > > > > > > [Non-text portions of this message have been removed]
      > > > > > > >
      > > > > > >
      > > > > > >
      > > > > >
      > > > > > [Non-text portions of this message have been removed]
      > > > > >
      > > > > > [Non-text portions of this message have been removed]
      > > > > >
      > > > > >
      > > > > >
      > > > >
      > > > >
      > > > > [Non-text portions of this message have been removed]
      > > > >
      > > >
      > > >
      > > >
      > > >
      > > > [Non-text portions of this message have been removed]
      > > >
      > >
      >




      [Non-text portions of this message have been removed]
    • prairiedog2332
      Martin, You have a very good point there. No matter what a plywood is called a builder should look for plies that are equal or close to it. Some marine grades
      Message 2 of 22 , Jun 6, 2012
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        Martin,

        You have a very good point there. No matter what a plywood is called a
        builder should look for plies that are equal or close to it. Some marine
        grades now are not totally equal though. I think they start off all
        equal but when sanded the outer plies get a bit thinner.

        The other thing of course is the glue. If the core layer is softer than
        the outer layers it can lead to glue starved plies even if the glue is
        waterproof. This can happen with the stuff coming from China. How do you
        know if it's coming from China? If it looks great and costs about 1/3
        the price or less than marine you can be assured it's from China.

        If in doubt I do the dishwasher test. Run a piece through the dishwasher
        about 6-7 times on full cycle. What I have found with Sureply is that
        the outer thin plies wrinkled a bit but never delaminated. One piece
        wrinkled on one side and the other darker side stayed flat. So it may
        work when glassed. If the layers are equal in an underlayemnt - no
        problem with wrinkling. Luan underlayment falls apart. OK for pattern
        makin in boat building.

        Crezon MDO layers are actually equal thickness as an overlay is applied
        after the sanding. It is heavier though as the cores are fir or a
        related species. But no need to glass it unless you want abrasion
        resistance.

        http://www.greatnorthernlumber.com/crezon.htm
        <http://www.greatnorthernlumber.com/crezon.htm>

        Nels


        --- In Michalak@yahoogroups.com, Martin Houston <mtnridr13@...> wrote:
        >
        > I've never seen Sureply but I checked out Ultraply at Menards & didn't
        like it. Seemed to have thick inner core & very thin veneers on either
        side. I know many good boats have been built from it but I used premium
        ACX. 3 equal thickness layers. Strong & takes screws & glue well.
        >
        >




        [Non-text portions of this message have been removed]
      • Martin Houston
        I  loooked at the Laun also. It was terrible. Warped, twisted & delaminating in the racks. The ACX is working well for me. Epoxy sealed & glassed of course.
        Message 3 of 22 , Jun 6, 2012
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          I  loooked at the Laun also. It was terrible. Warped, twisted & delaminating in the racks. The ACX is working well for me. Epoxy sealed & glassed of course.



          ________________________________
          From: prairiedog2332 <nelsarv@...>
          To: Michalak@yahoogroups.com
          Sent: Wednesday, June 6, 2012 9:24 AM
          Subject: [Michalak] Plywood?



           


          Martin,

          You have a very good point there. No matter what a plywood is called a
          builder should look for plies that are equal or close to it. Some marine
          grades now are not totally equal though. I think they start off all
          equal but when sanded the outer plies get a bit thinner.

          The other thing of course is the glue. If the core layer is softer than
          the outer layers it can lead to glue starved plies even if the glue is
          waterproof. This can happen with the stuff coming from China. How do you
          know if it's coming from China? If it looks great and costs about 1/3
          the price or less than marine you can be assured it's from China.

          If in doubt I do the dishwasher test. Run a piece through the dishwasher
          about 6-7 times on full cycle. What I have found with Sureply is that
          the outer thin plies wrinkled a bit but never delaminated. One piece
          wrinkled on one side and the other darker side stayed flat. So it may
          work when glassed. If the layers are equal in an underlayemnt - no
          problem with wrinkling. Luan underlayment falls apart. OK for pattern
          makin in boat building.

          Crezon MDO layers are actually equal thickness as an overlay is applied
          after the sanding. It is heavier though as the cores are fir or a
          related species. But no need to glass it unless you want abrasion
          resistance.

          http://www.greatnorthernlumber.com/crezon.htm
          <http://www.greatnorthernlumber.com/crezon.htm>

          Nels

          --- In Michalak@yahoogroups.com, Martin Houston <mtnridr13@...> wrote:
          >
          > I've never seen Sureply but I checked out Ultraply at Menards & didn't
          like it. Seemed to have thick inner core & very thin veneers on either
          side. I know many good boats have been built from it but I used premium
          ACX. 3 equal thickness layers. Strong & takes screws & glue well.
          >
          >

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




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