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Thread: Knot free mast wood

  1. #1
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    Default Knot free mast wood

    It has come to my attention as I search for suitable wood for the sharpie's masts that maybe poplar would be ok. I believe this is Loriodendron tulipfera, otherwise called tulip or white wood. It is locally available and its properties, specific gravity, modulus of rupture, and modulus of elasticity look good. I would need to laminate and scarf. The rot resistance is poor but I think I can deal with that.

    Does anyone have comments about it?

  2. #2
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    Default Re: Knot free mast wood

    I was under the impression that the name for poplar in the US was cottonwood? No Douglas fir available where you are?
    The definition of stupid has got to be the belief that more guns will negate the bloodshed done with guns.

  3. #3
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    Default Re: Knot free mast wood

    I've used a lot of poplar for secondary wood in furniture and it's just super for that. But I'd never think it would be suitable for a mast.

    Jeff

  4. #4
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    Default Re: Knot free mast wood

    I think Rob White used it for the masts on his little boats. Of course his was probably air dried old growth not over kilned big box crap.

  5. #5
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    Default Re: Knot free mast wood

    I'd use generic pine over poplar if I had to use lumberyard materials.

  6. #6
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    Default Re: Knot free mast wood

    Isn't Poplar halfway to balsawood ?

  7. #7
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    Default Re: Knot free mast wood

    Tulip,Yellow poplar is waaaay different from aspen and cottonwood.
    Stronger,harder,heavier and stiffer than many softwoods,except maybe Doug Fir,larch (tamarack)or decent SYP.
    Probably not stiffer than spruce.
    It also expands a LOT when it takes on moisture.
    R
    Sleep with one eye open.

  8. #8
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    Default Re: Knot free mast wood

    Keeping water out will be paramount for any longevity. Be sure to use only heart wood as well.

  9. #9
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    Default Re: Knot free mast wood

    Tulip Poplar AKA Southern Yellow Poplar is a boon to the lumber industry because it is able to be plantation grown in a very short amount of time. It is available everywhere and is one of the cheapest hardwoods available. It is a default species for furniture and millwork for “paint grade” projects. I stopped using it for furniture cabinetry and millwork a decade ago for the simple reason that it moves too much seasonally. It was once commonly used near me for exterior trim on houses and proved to be unsuitable because of it’s fondness for rotting, and moving too much with the seasons. I can’t believe it is appropriate for a mast. I am building a mast of spruce which I purchased from a lumberyard by pawing through their stock of 14’-16’ 2x10s. I need only one or two more. The ones I selected are straight, nearly clear, and vertical grain. It is cheap enough that knots can be ripped out and set aside for dunnage and still be affordable. In a month’s time it has cured to <10% MC.

  10. #10
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    Default Re: Knot free mast wood

    I really don’t think Poplar is any more rot prone than Spruce. I would consider it for a birdsmouth spar.

  11. #11
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    Default Re: Knot free mast wood

    Steven could be right on with the rot potential. The issue I found is that the glue lines move enough to crack and become visible, even indoors. Outdoors this was a worse problem, coupled with a tendency to cup, resulting in total failure. It would also be unlikely to find quartersawn. This is not to say that it is no good. I’m only pointing out issues I’ve had.

  12. #12
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    Default Re: Knot free mast wood

    When I was considering what species to use for the masts on my Coquina I consulted the forum as you have. Of course the “wood snobs” said that if I used ANYTHING other that Sitka spruce I’d be labeled a heretic, the allies would lose the war and of course I’d dismast.
    Well I took a look at the engineering numbers for poplar with a good friend who happens to be a materials engineer for Lockheed (helped design the F-22). Poplar had very similar strength to spruce, for $2 a board foot as opposed to $27. Oh and you can actually get it here.
    So I increased the mast diameter 1/16” to make up for the slight deficit in strength.
    That boat was built 4 years ago. It’s been sailed HARD and no issues. Oh and another Coquina was built nearby and he used Poplar too. He’s had no issues either.
    Avoid the sapwood, don’t get it at a big box store, and you should be fine. If you really want to go with DF there is a place here in ATL that has it. Randall Lumber neat the Coke Headquarters.
    Fight Entropy, build a wooden boat!

  13. #13
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    Default Re: Knot free mast wood

    too brittle and the movement/effects of moisture issues make glue lines susceptible to fracture IMHO

    sw
    "we are the people, our parents warned us about" (jb)

    steve

  14. #14
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    Default Re: Knot free mast wood

    Several years ago I was called to repair a mast that had had a new four foot section splice on at the butt and through the partners. The repair was less than three years old and the poplar that was used for the new section was, literally, turning turning to mush! fortunately there was still sound spruce that made up the rest of the mast to accept a splice of a new section made of spruce.

    Please do not think I am against the use of poplar I make most of the drawers and other cabinetry out of it for my shop. It looks good and is really nice to work. It just does not belong on a boat, anywhere!
    Jay

  15. #15
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    Default Re: Knot free mast wood

    Sitka Spruce (Picea sitchensis)

    Common Name(s): Sitka Spruce
    Scientific Name: Picea sitchensis
    Distribution: Northwestern North America
    Tree Size: 130-160 ft (40-50 m) tall, 4-6 ft (1.2-1.8 m) trunk diametebr /> Average Dried Weight: 27 lbs/ft3 (425 kg/m3)
    Specific Gravity (Basic, 12% MC): .36, .42
    Janka Hardness: 510 lbf (2,270 N)
    Modulus of Rupture: 10,150 lbf/in2 (70.0 MPa)
    Elastic Modulus: 1,600,000 lbf/in2 (11.03 GPa)
    Crushing Strength: 5,550 lbf/in2 (38.2 MPa)
    Shrinkage: Radial: 4.3%, Tangential: 7.5%, Volumetric: 11.5%, T/R Ratio: 1.7






    ommon Name(s):
    Poplar, Tulip Poplar, Yellow Poplabr /> Scientific Name: Liriodendron tulipifera
    Distribution: Eastern United States
    Tree Size: 130-160 ft (40-50 m) tall, 6-8 ft (1.8-2.5 m) trunk diametebr /> Average Dried Weight: 29 lbs/ft3 (455 kg/m3)
    Specific Gravity (Basic, 12% MC): .40, .46
    Janka Hardness: 540 lbf (2,400 N)
    Modulus of Rupture: 10,100 lbf/in2 (69.7 MPa)
    Elastic Modulus: 1,580,000 lbf/in2 (10.90 GPa)
    Crushing Strength: 5,540 lbf/in2 (38.2 MPa)
    Shrinkage: Radial: 4.6%, Tangential: 8.2%, Volumetric: 12.7%, T/R Ratio: 1.8


    $27 a BF vs. $2 a BF.
    Fight Entropy, build a wooden boat!

  16. #16
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    Default Re: Knot free mast wood

    Quote Originally Posted by Reynard38 View Post
    Sitka Spruce (Picea sitchensis)

    Common Name(s): Sitka Spruce
    Scientific Name: Picea sitchensis
    Distribution: Northwestern North America
    Tree Size: 130-160 ft (40-50 m) tall, 4-6 ft (1.2-1.8 m) trunk diametebr /> Average Dried Weight: 27 lbs/ft3 (425 kg/m3)
    Specific Gravity (Basic, 12% MC): .36, .42
    Janka Hardness: 510 lbf (2,270 N)
    Modulus of Rupture: 10,150 lbf/in2 (70.0 MPa)
    Elastic Modulus: 1,600,000 lbf/in2 (11.03 GPa)
    Crushing Strength: 5,550 lbf/in2 (38.2 MPa)
    Shrinkage: Radial: 4.3%, Tangential: 7.5%, Volumetric: 11.5%, T/R Ratio: 1.7






    ommon Name(s):
    Poplar, Tulip Poplar, Yellow Poplabr /> Scientific Name: Liriodendron tulipifera
    Distribution: Eastern United States
    Tree Size: 130-160 ft (40-50 m) tall, 6-8 ft (1.8-2.5 m) trunk diametebr /> Average Dried Weight: 29 lbs/ft3 (455 kg/m3)
    Specific Gravity (Basic, 12% MC): .40, .46
    Janka Hardness: 540 lbf (2,400 N)
    Modulus of Rupture: 10,100 lbf/in2 (69.7 MPa)
    Elastic Modulus: 1,580,000 lbf/in2 (10.90 GPa)
    Crushing Strength: 5,540 lbf/in2 (38.2 MPa)
    Shrinkage: Radial: 4.6%, Tangential: 8.2%, Volumetric: 12.7%, T/R Ratio: 1.8


    $27 a BF vs. $2 a BF.
    So, what's the secret to keeping it from rotting?

  17. #17
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    Default Re: Knot free mast wood

    Submerge it in wood preservative for a while, perhaps in ethylene glycol and borax, then seal it well. That would stabilize it as well.

    Get it pressure treated.

    By the time you do that you may as well have purchased another species.

    How about Cypress? Small knots actually make it harder to split, and it grows nearby.

  18. #18
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    Default Re: Knot free mast wood

    Quote Originally Posted by johnw View Post
    So, what's the secret to keeping it from rotting?
    I dunno, maybe the same as Sitka which I understand isn’t exactly durable either.
    I avoided sapwood, made it birdsmouthed and applied 3 coats of epoxy before the varnish went on.
    Last edited by Reynard38; 06-08-2018 at 03:38 PM.
    Fight Entropy, build a wooden boat!

  19. #19
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    Default Re: Knot free mast wood

    The secret of longevity for any wooden mast is not to neglect maintenance in the form of renewing the finish at least every two years. Once a year is best but, in drier climates two years can be gotten away with if you keep an eye on the wood. Varnish is preferred over paint as it will allow full visual information on what is going on within the wood. Larry Pardy has always said that it is like having an Xray machine at your disposal 24/7 at no charge. Keeping the finish in good condition is a must for any wooden mast.

    I have a spruce mast in my yard that I use as a flagpole. It is the top half of the mast from my Common Sense Sloop #5. It broke due to a rigging failure. The boat and mast were both built in 1935. That is eighty three years ago and it has not shown any signs of rotting yet!

    Fir is a bit heavier than spruce and is slightly more rot resistant than spruce. It will give good service, as well, if cared for properly.
    Jay
    Last edited by Jay Greer; 06-08-2018 at 03:53 PM.

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