Strip Planking Videos

Discussion in 'Boatbuilding' started by Mat-C, Aug 12, 2011.

  1. Oceansky
    Joined: Jul 2007
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    Oceansky Junior Member

    Much of the muchness mate. Bead and cove planks work well with square section planks or hulls having long runs (multihulls for example) but the problem lies in the fact that since most strip plank composite cores are anything from 6mm upwards, having a square section here is ridiculous. For example a 9mm square section means a lot of planking and glueing. Thats why most plank with rectangular planks.

    Another problem using bead and cove rectangular planks means you still have to fit the planks (if you don't want edge set) which means that you have to either cut off the bead or the cove. Cut off the bead and you've cut a lot of filling to do in the cove. Cut the cove and you'll have trouble working the glue around the bead. I've mucked around with bead and cove and personally I found the whole idea a waste of time and money. It was ok planking the topsides, but planking the turn of the bilge and the bottom plate was damn frustrating.

    Overall bead and cove , like all things, has it's place. What you do is up to you !!

    Any weight gained or lost here is nothing compared to the weight gained or lost when it comes to fitting out. Plywood comes in so many weights (densitys) which I've found through testing that don't match the manufactureer's specs or the builders decides to use cheap heavy plywood to save money. This doesn't take into account where the builder change the design (add cabins/ move interior joinery or add or subtract from.) This is what you've got to keep and eye on.

    I did some testing today on some gaboon plywood which was sent to me to test (mechanical properties and density). They advertised the plywood had a density off 430 kg.m^3, yet on testing it was between 580 - 600 kgm^3. That is a huge difference and overall, it will add a lot to the hull weight. This is what you need to be watching out for.. more than anything.

    I actually wrote an article on this a while back, but that's another story.
    Here's the link:
    http://www.bowdidgemarinedesigns.com/Bowdidge_Marine_Designs_1/Plywood_Weights_Article.html

    Hope this helps
    Anyway, have a good one and havagreatweekend
    Mark
     
  2. Landlubber
    Joined: Jun 2007
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    Landlubber Senior Member

    Thanks Mark, Nice to see someone post a video that shows how simple strip planking can be, there are many potential boatbuilders out there that have never actually seen it done before, your method is of course one of a million different versions, but at least it is out there, ta mate. John
     
  3. Oceansky
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    Oceansky Junior Member

    Your welcome
    have a good one
     
  4. Oceansky
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    Oceansky Junior Member

    G'day all,
    One thing that I didn't mention here or on the video, but is mentioned in the plans is regarding the glue mixture.

    You don't use straight glue powder, but you mix 50/50 cabosil and microballoons. This way the cotton flock creates the binder within the mixture and using microballons reduces the overall weight of the mix.

    Hope this helps
     
  5. Mat-C
    Joined: May 2007
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    Mat-C Senior Member

    Thanks Mark.
    So at some point in plank thickness you would suggest changing to a "wet" gluing method? And I guess that thickness would depend on the amount of arthwartship curvature...
    Looking fwd to the next installment of the videos...:p
     
  6. Oceansky
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    Oceansky Junior Member

    G'day Mat-C,
    Wet gluing..hmmm. It would all depend on the boat but more importantly the type of build.

    Lets say I'm building a traditional strip plank boat where the strength of the boat or build is dependant upon the strength of the plank and is then overlaid with a thin layer of glass (ie 200gm or 6oz cloth) on the outside for abrasion. Here I would plank as normal (wet glue) because this type of build typically requires a thicker plank when compared to strip plank composite. I would then plank as per the "wet glue" method, however I would use planks that are square in section to make it easier to plank.

    As our designs are engineered as composite strip plank, not as a traditional strip plank design, in this regard, the planks can be thinner and the overall strength of the build is not dependant upon the plank mechanical properties (except for core shear strength) but on the inner and outer laminate mechancial properties. This means I can plank the boat using the "dry method" as the overall build is then laminated or sandwiched between the glass.

    Does this help?
     
    Last edited: Aug 19, 2011
  7. rwatson
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    rwatson Senior Member

    Hi Mark

    Thanks for the long phone call this morning - found it very informative.

    I had considered this technique some time ago,
    http://www.boatdesign.net/forums/wo...oblems-could-building-method-cause-24170.html

    so I was wrapt that it actually will work, and even more important, that there was someone who could do the engineering calcs on it,

    I think the method is going to save a lot of people a lot of work.
     
  8. bretag
    Joined: Sep 2010
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    bretag Junior Member

    Dry strip method test

    As a check on 'capillary' epoxy penetration between strips, I set up 3/4" thick strips at gaps ranging from approx .039" down to approx 0.020".
    Using unthickened epoxy and painting from both sides, penetration was complete in every case from 20-25thou and then gaps started showing up. Worst results were at 39thou but even then no less than 70% of the surfaces were bonded.These tests were done both with the gaps both horizontal and vertical. Max spillage or dripping and least coverage occurred with vertical gaps. There was virtually no dripping at 0.02" gap.
    Gaps were parallel in every case, however it would seem that providing the gap ranged between these test widths on any adjacent planks that the bond area would be between 70-100% in every case. Adding glass plus further epoxy at each side will surely result in 100% bond in every case.
    Am I missing something?
    Comments will be much appreciated
    Bretag
     

  9. rwatson
    Joined: Aug 2007
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    rwatson Senior Member

    Slight warming of the epoxy with a heat gun improves flow if the temp is cool. If you are putting fg cloth on both sides, all this testing is purely academic. The bond between planks is not critical.
     
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