Norway Spruce for strip planking?

Discussion in 'Materials' started by Ranger1973, Oct 1, 2012.

  1. Ranger1973
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    Ranger1973 Junior Member

    Hi All...
    I was unsure whether to start this(new)thread or just post this question into someones else's thread.O well-apologies if i'm using bad etiquette...forums etc are new to me.I am a new member but have looked at boatdesign.net a helluvva lot.Please bare with me!.
    Anyway...my question is this:-Is Norway Spruce-or in fact any type of spruce (not withstanding Sitka,an obvious building material) a viable option for strip planking.The boat will be fully encapsulated with glass on the outside and epoxied and semi glassed on the inside.My thinking is this-even if the wood is only slightly rot resistant is it really an issue as the boat will be fully skinned and watertight anyways!I know that alot of Marine Ply has layers of spruce in anyhow and the only thing that makes it 'Marine' is the fact it has no cavities and the glue used to laminate the wood together is water and boil proof...so really is the choice of wood really relevant(within reason...obviously no one would try to sail a boat made out of mdf or chipboard:p...would they????).Also i have access to a lot of spruce as a building material(which in part is driving this query).This boat DOES NOT need to last more than 30 years.I apologize once again for the large post and if i'v used bad etiquette-and i look forward to any help,opinions or directions on this subject.Thanks.:D
     
  2. Ranger1973
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    Ranger1973 Junior Member

    Sorry-a quick addition to my previous post...the same question but aimed at FIR as a building material instead of SPRUCE!thanks people.
     
  3. TeddyDiver
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    TeddyDiver Gollywobbler

    I surely hope so :rolleyes: bcs that's what I use..
    Seriously.. Yes it is :D
     
  4. Ranger1973
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    Ranger1973 Junior Member

    Haha...thanks.:D
    And what is your opinion of fir for strip planking?Or indeed for stringers and othe r structural members...good wood to use?I'm in the early stages of designing and planning a boat build...its a long way off however.
    Basically what im trying to do is get a feel for the materials im going to be,or should be,using in the build.I had in mind white oak as i have access to this material but in smaller quantities-however im not too keen on oak as there are varying opinions on the properties of how it bonds with epoxy and the interaction of saltwater with epoxy/glues.
    As i say-how do you feel as regards fir?.Not necessarily douglas fir either.
    Again thanks.
     
  5. Petros
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    Petros Senior Member

    anything and everything has been used to build boats, even bamboo. Any reasonably clear straight grained wood can be used, however on larger projects that will be kept in the water for long periods of time, high degree of rot resistance is very desirable.

    woods with high strength to weight ratio are desirable, wood with a high natural rot resistance is desirable, wood with a fairly high cross grain compression strength makes wood good for decks, rub strips and elsewhere subject to impacts and abrasion.

    For strip planking that will be protected by GRP on both sides, most like to use cedar, which is very light compared to hardwoods. Norway spruce is fairly light if I remember correctly, and should work fine. Many firs, like douglas, are heavy for a softwood, a lighter weight species would likely work out fine. I would think for strip plank you want something that is dimesionally stable, low sap and takes adhesives well.

    Might do a few tests to see how it bonds compared to western red cedar and sitka, if you get comparable results you will likely have no issues. a word of warning however; if the reason you are considering this is to save money, compare the money saved against the total cost and the amount of work you will invest into this project, is it worth the savings of using unknown quality? A small boat build for fun, and not expecting it to last for very long, a reasonable risk. but if investing a lot of time and money into a large craft, not likely worth the small savings.
     
  6. Ranger1973
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    Ranger1973 Junior Member

    Thanks for your input.Yes-i hear what you are saying as regards the economical sensibilities ie:-is it false economy to use an inferior material when building as it will only rebound back at you years (maybe even months) down the line-and most probably when you least need it the most...at sea!
    I will take your advice and take some samples of the wood and experiment with it,do various tests using different epoxies,thicknesses of wood,strength tests-load bearing,shear test etc...i will also subject the material to submergence tests as well and also perform the same tests wet as opposed to dry.I will also experiment by seeing how much force it can take-its tensile strength per square inch...i will even employ a sledgehammer:D...excessive?maybe-but i think prudent!
    As i said in my earlier post,it is very convenient for me that i do have access to a very large supply of good quality timber,and can get quarter sawn/rift sawn spruce/fir,which would save me a lot of money.However,this won't be done at the expense of safety and good practice however convenient.As far as im aware fir and spruce as a genus do have relatively good,true grain structure-although the rot decay varies from species to species.
    As far as im aware balsa wood is absolutely terrible when it contacts with water-yet this material has been used by boat constructors in varying degrees in the past with sometimes disastrous consequences.Is that an observation you yourself would agree with?Also does my plan of testing the materials i MAY be using seem sound?
    Thanks.
     
  7. gonzo
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    gonzo Senior Member

    Spruce is fine for strip planking. It has been used in many boats, the same as white pine, without any sheathing. If you are going to fiberglass over it, spruce makes a good core because the adhesion is good. Balsa is used with success, which is a much softer wood.
     
  8. Ranger1973
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    Ranger1973 Junior Member

    And are the various species of fir also good material to use for planking?I'm aware that douglas fir is popular among builders and has a well reported track record in boat construction-(as far as im aware douglas fir isn't actually a true FIR regardless of its name).
    I'm more querying the other types of fir available as strip planking.
    :)Again,thanks.
     
  9. gonzo
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    gonzo Senior Member

    Fir is a really good material for planking. However, it splinters quite a lot. Also, because the grain is very coarse, it doesn't fair well. If you are going to fiberglass over, it doesn't matter.
     
  10. Ranger1973
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    Ranger1973 Junior Member

    Thanks Gonzo.In your opinion do you think that fir will be a good material for the stringers,girders,keel etc...basically for the main structure of the hull that the planking will go onto?.
    Is it feasible to construct a boat almost entirely out of fir?.:)
     
  11. gonzo
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    gonzo Senior Member

    In North America many work boats were constructed entirely of Douglas fir with good success. I have built several sport fishing boats with stringers and other timbers of fir. These are 40 plus knot boats that go out in fairly rough weather on a daily basis.
     
  12. Ranger1973
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    Ranger1973 Junior Member

    Sounds good!The boats appear to be very reliable from what your saying.
    So now i'm pretty sure that the boat will be planked in spruce or fir,stringers and keel then also in spruce/fir and using marine ply as bulkheads.I'm debating with myself now as to whether or not to use white pine for the bridge head area,effectively making the bottom parts of the boat in fir/spruce and the top half in pine.I actually want to leave the top half of the boat in just epoxy/wood,(several layers)so the grain/wood can be seen-this is for purely aesthetic reasons.How THICK would you recommend the planking should be?Lets say the boat is between 28-30 foot L.O.A.-I was imagining it planked in 2 inch by 1 inch strips.
    ANY help,suggestions,advice or general counsel on this (and i promise there will be alot more questions in the next year regarding this project;)) will be extremely well received by myself.
    Thanks.
     
  13. Stephen Ditmore
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    Stephen Ditmore Senior Member

  14. Ranger1973
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    Ranger1973 Junior Member

    Cedar would be very welcome and an ideal choice-however,the reason for my interest and querying fir/spruce and indeed pine is because,as i mentioned in an earlier post,it is a readily available commodity/material for me to procure.If it proves to be an acceptable building material then i will be saving myself alot of money-and seeing as i really don't have a lot of money to begin with,is very convenient for me:D....!!!haha....
     

  15. Stephen Ditmore
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    Stephen Ditmore Senior Member

    Then I suggest letting it dry and coating all end grain with at least 2 layers of epoxy prior to assembly. Every saw cut, coat the end grain. After assembly I'd coat everything with 1 coat of epoxy or epoxy primer paint, then with a polyurethane paint or clear coat with plenty of UV protection.

    Paul Oman at www.epoxyproducts.com offers the products described above, but also swears by Aluthane, claiming this 1 part product actually seals better than epoxy. So it's an option for sealing the end grain and as an undercoat if you don't like 2 part products. He also offers a 1 part clear coat called Crystalac/CrabCoat UV BLOCKER. You should probably buy from a UK supplier, but Paul's website is a good information source if you can tolerate its wackyness.

    I've done one strip plank job that turned out badly, so I'm no expert, but if I were to do another I'd use TightBond III to glue the strips together, and I wouldn't do any gluing in less than 15 degrees C (59 degrees F).
     
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