How to correctly prepare pine for mast?

Discussion in 'Materials' started by laukejas, Feb 16, 2012.

  1. laukejas
    Joined: Feb 2012
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    laukejas Senior Member

    Hello everybody,

    I'm building a small sailing catamaran this summer (converted from bottle raft, if you are interested, old raft video is here). I'm looking for a new mast, since the one I used before broke in half (it was only 2.5cm diameter steel). I think I'll try to get a fine Lithuanian pine mast, 5-6 metres long (still working on sail plan), 10cm diameter. I think I'll cut it down in the forest, since I can't get the right length and diameter to buy.

    However, I'm so new at boat building, that I don't know how to prepare that pine correctly. I heard of making grooves in tree like here to make resin go away. But that takes a long time, I think, and I have about 3 months from now until I start working on that mast. Is making resin go away so important?

    First of all, what's the best season to cut down a pine? Is now (middle winter) okay, or should I wait for spring/summer?

    Next thing, how to cut down tree correctly, so it wouldn't fragment or splinter inside? Won't vibrations from electrical saw harm tree's integrity? Maybe hand saw is better?

    Afterwards I cut it down, should I peel the bark away, or is it better to wait for summer before that? Should I dry that tree, or instead, keep it submerged in water?

    If I need to dry that tree, would just leaving it in living room until summer be enough, or does it need special environment? (I have none).

    And lastly, after drying it (if it is necessary), and making the mast out if it, should I cover it in varnish, or not? If yes, what kind of varnish? (don't tell me brand names, just type, since I live in Lithuania, and I doubt anyone here is living there too, so most probably I won't have in my store what you have in your country).

    That is a lot of questions, but I don't want to screw up this, my budget is very very limited, so I have to find out whole procedure correctly. I would very, very much appreciate if anyone could help me out here, and answer that bunch of questions.

    Thank you for your time.

    P.S. By the way, optional question: do you think that the mast of these proportions would hold sloop rig, 5.2 square meters gaff, and 2.7 square meters jib without shrouds and stays? If not, I can try looking for thicker mast, or hook up shrouds and stays.
     
  2. alan white
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    alan white Senior Member

    Good Lord! What you need is a lumber yard, not a forest. My suggestion is you make sure the wood you want is an acceptable species, and then try and find a straight, full length piece of stock.
    Masts can be built up from several pieces too, either full length strips glued together or several full section pieces scarfed together.
    No treatment is required except proper drying, something you can check with a meter, but is easier done by an experienced woodworker looking at the wood.
    Wood can be cut throughout the year. Sap runs along the outside of the tree.
     
  3. Stumble
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    Stumble Senior Member

  4. PAR
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    PAR Yacht Designer/Builder

    Cutting a tree of questionable species down and attempting to use it as a mast in a few months, is just asking to be quite disappointed.

    Milling your own lumber is a noble effort and one I've done many times, but I'm also willing to wait for the wood to "season" naturally or accelerated in a solar kiln.

    You don't need, nor frankly should you be falling your own timber. Judging by your questions and general tone of you post, the best advice you could receive is what Alan has mentioned; go to the lumber yard.

    Seasoning you own lumber can take years, so unless you have lots of time, you're best off buying milled and planned dimensional stock, from your local lumber yard. Maybe you can trade some freshly cut stock for milled.

    The next best advice you could receive is to start reading up on wood working and boat building practices. As to your rig's needs, you haven't provided enough information to size the mast properly, but assuming a 4 meter mast with 8 sq. meters of area, stayed gaff, with a masthead jib you're looking at a minimum of 55 mm at the heel and tapering to 40 mm above the hounds on a solid stick. A solid Douglas fir mast of these dimensions will weigh over 7.5 kilo, while a solid Sitka spruce mast of the same dimensions will weigh less then 6 kilo. Conversely, if the mast was hollow, the dimensions would be 60 mm at the base, again tapering to about 43 mm at the head (above the hounds). A mast of these dimensions and 20% wall birdsmouth construction, would weigh about 2 kilo if Sitka and about 3 if Douglas fir.
     
  5. laukejas
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    laukejas Senior Member

    First of all, thank you for your answers.


    Thing is, I understand that going to "local lumber" is best thing to do. Sadly, I've done it already. They don't have the tree I need. They sell only 6 metres long pieces of 20 cm diameter, which means I would have to literally reduce it to half with plane. And that is one hell of work. Problem is, these lumbers sell trees in pre-determined sizes and thicknesses. I tried many of them - all said the same: cut down your own tree.

    So here I am.

    Stumble, I red your link, and, well, I don't know how this could be easier than cutting down a tree, since I don't have a half of that equipment. And that requires quite an experience with woodwork (for example, precisely preparing these eight parts).

    PAR, thanks for the information. By the way, why do you say "questionable species"? As I red in various sites, pine (many kinds of it) is main wood to be used for masts. Of course, most of types don't even have a name of "pine", but that is similar kind. Anyways, that's the closest to the perfect type of tree that I can get.

    I understand that I'm undertaking quite a job here, but as I said, I have no other way: lumbers don't have that kind of trees, I don't have enough equipment to make mast from parts, so I have to fall back to cutting down a tree myself.

    I understand that I lack a lot of knowledge here, but at least I've got time, so if you could provide any more useful information, I would be grateful.
     
  6. die_dunkelheit
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    die_dunkelheit NA Student

    Hold on a second. You don't want a single piece of material from the lumberyard to machine a mast out of. What these gentlemen are talking about is many pieces joined together. Scarf joints to get your length of stock and then other joinery to make the profile. I'm personally a fan of the look of the bird's nest masts, damn strong too. The result would be a hollow mast made of many strakes around a circle or oval, tapering to the top won't be too difficult and you'll end up far lighter and stronger than a solid mast. That may sound like a lot, but your principle tools will be skill-saw, tape measure, and a pencil. Woodenboat magazine has published a great step-by-step in an issue not too long ago in which they build a box mast (correct me if that's the wrong name, 4-sides, front and back rounded to give oval appearance). I'll dig the issue out and give you the issue info do you can find it, or I may just scan & email it too you...
     
  7. hoytedow
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    hoytedow Carbon Based Life Form

  8. laukejas
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    laukejas Senior Member

    Hm. For sure I don't have skill saw. So the only thing I can do is buy already cut pieces. I found some in my local store . But wood is "mixed". So that is bad. I don't think I'll get pine tree I'm looking for. And I don't have any means to cut these pieces myself. I have a hand saw and hand plane.

    By the way: these pieces cost 1,38 euros each. I need 8 of them for that round shape, and 3 rows to get 5 metres (since they are only 1.8 metres long). That comes to 24 pieces, that means 33 euros. Well... That lumber which offered me 5 meters long 20 cm thick tree said it would be 20 euros. Well... I probably miss something here. This is both more expensive (not counting expenses for glue) and complicated.

    Could someone explain why would I fail if I would just simply cut down a tree?
     
  9. hoytedow
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    hoytedow Carbon Based Life Form

    Easy hollow mast using what is available:

    Screw the planks together and plane the corners till they are rounded and not sharp.
     

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  10. PAR
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    PAR Yacht Designer/Builder

    Again, if you read up on wood working and general boat building practices, you'll discover how to make long pieces from shorter, how to make hollow spars and all the other things we take for granted.

    If you're looking to specify a tree species, there are several sites to look up physical properties, so you can compare what you have locally, to what is considered desirable. You're probably going to want a spruce or fir, not the typical pines that are available. The species selected should be light (under 30 pounds per cubic foot, preferably under 28), straight and tight grained, free of defects (knots, checks, pith, etc.), should accept glue and fasteners well and it's physical attributes should show a marked ability to tolerate compression loads (for it's weight). Solid, grown masts are the least desirable option, particularly on a boat of the size you have.

    The best thing you can do now is go talk to some local boat builders and see what they use and where they get it.
     
  11. laukejas
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    laukejas Senior Member

    PAR, thank you for your effort, but please understand, I do not have that kind of selection here. As I said, these wood pieces I linked you is probably all that is possible to get in my country. That "mixed" wood doesn't sound good at all. If I can get decent wood, probably the only way is either to cut it down myself, or buy that 5m on 20cm pine, and remove half of it's thickness.

    I, in fact, did some research before posting here, that's why I'm talking about that pine. I heard that spruce and fir is not good because of branches (which weaken the trunk). Is that wrong?

    I understand about that solid wood. But what can I do? I would really like to make mast from pieces that you showed in links, but I can't find good timber for it. Believe me, choice in my country is near to zero.

    And there aren't any local boat builders. There are maybe 4-5 amateurs in whole country, including me. And I don't know them.
     
  12. alan white
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    alan white Senior Member

    Spruce and fir happen to be very good woods for mast building, though some pines have good properties (stiffness, strength per weight, straight grain). Still, look around the world and you'll see that spruce in particular seems to be availabler in most places and many varieties are preferred for spar building.
    Any small tree, one requiring only light dressing from the original dimensions, will have plenty of small knots. This is normal and the knots shouldn't detract from the spar too much as long as they are small and tight.
    Maybe there is a pine species near you that grows fewer branches down low---- I don't know, but very possible. Local boat builders always have good information.
    It's hard to suggest options for someone who lives in an area where life is so different, where availability of certain manufactured materials is difficult or impossible, and especially someone with very little woodworking experience.
    Still, spar woods are not that rare throughout Europe so I would still look for a piece of seasoned wood, maybe a dry section of the right sized pine, spruce, or fir sapling----- maybe an old pole that had been used for a fence post.
    Learn how to shape a mast with hand tools (a power plane, hand held, is a fantastic tool to shape spars with if you can borrow or rent one, but otherwise an old style hand plane is time-consuming but effective.).
    Consider an aluminum section for the mast if you need a substitute until you find the right wood.
     
  13. laukejas
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    laukejas Senior Member

    Thanks for the info. As it happens, spruce and fir in Lithuania look like this, and pine looks like this, so pine looks with far less branches, therefore, should be better... As I was told before.

    And believe me, I've been looking for a mast for more than a month before I desperately wrote to you here. I still hope I can find a solution on how to make hollow mast out of wood strips, or I'll have to cut down a whole tree, which, as I see from people posting here, isn't a good idea.
     
  14. alan white
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    alan white Senior Member

    You can build a hollow box section mast from approx. 18 mm thick boards. This is rarely done on small craft--- usually a solid wood mast is used. Anything more complicated, like a birdsmouth mast, is way beyond your skill level and way beyond what's needed anyway.
    As a matter of fact, a box section might be ideal for you given your situation. A mast like that can have many pieces scarfed together, and it's the poor man's lightweight mast, strong and light and cheap.
     

  15. laukejas
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    laukejas Senior Member

    Man, I'm lost here. You say that "on small craft, usually a solid wood mast is used", while PAR said that "Solid, grown masts are the least desirable option, particularly on a boat of the size you have." Whom I am to believe?
     
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