Suitable Substitute for Sitka Spruce?

Discussion in 'Materials' started by CatBuilder, Mar 27, 2010.

  1. CatBuilder

    CatBuilder Previous Member

    If designer specs 3/4" Sitka Spruce, what is a suitable replacement wood for this, given that Sitka Spruce isn't readily available to me on the East Coast?
  2. alan white
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    alan white Senior Member

    Many spruces will do, and douglas fir will also serve, though a bit heavier.
    Adirondack spruce is what Martin guitar has chosen as a replacement for sitka, which used to be used on all their guitars. I would say that Martin has likely done their homework, as some of those guitars cost around 100k.
    Believe it or not, the qualities that make a guitar sound good are also the qualities that make wooden structures last and maintain strength.
  3. Boston

    Boston Previous Member

    interesting post Alan
    Ill look into Adirondack spruce soonest I can make a few calls monday
  4. CatBuilder

    CatBuilder Previous Member

    Thanks for the idea, Alan. I'll take a look at the various properties of spruces and see what can be done.
  5. rasorinc
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    rasorinc Senior Member

  6. Boston

    Boston Previous Member

    well that was really interesting
  7. rasorinc
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    rasorinc Senior Member

    Boston, another wood you should consider is Ironbark aka Eucalyptus. I did a lot of furnature out of it finished it as mahogony with teak oil tinted. One supplier had a ton of it for 3.00 a BF all 2x and various widths and length. It is farmed now extensivly here, south america and central america. Very strong, straight grained and plentiful. Weyhaeuser marketed it as LYPUS FOR HARDWOOD FLOORS BUT NO MORE. A weyhaueser plant here has some left over that I'm trying to buy. When real dry it is not as heavy as specs say and wonderful to work with. If a plan calls for a nominal 2 x 6 you could use 1 x 6 as it is so strong. Google it for suppliers. Stan PS really no downside to it. The hybrids now do not have the poor chacteristice some native lumber had.
  8. Boston

    Boston Previous Member

    thanks Stan I will keep that file on my desk top and read through it soonest

    I'll need to check the actual weight as my whole reason for getting down on making this decision is so I can do a decent weight budget and really get my design past the sketch stage

    in this regard Poplar and white pine are hard to beat although neither has met with much approval

    Im just kinda kidding myself until I do a mass budget at this point
    I kinda guessed as I went with the initial sketches but at this juncture I need some real numbers

  9. jantheron
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    jantheron Junior Member

    I use eucalyptus (saligna) quite extensively on my lightweight canoes for stems, keelson and inwales. For outwales, you have to select the darker parts of the plank... they are normally a bot harder. It does have the tendency to tear out when planing though. Even with a razor sharp low-angle block plane.
  10. Boston

    Boston Previous Member

    when a wood is harder than its tensile strength you end up with a lot of tear outs
  11. dskira

    dskira Previous Member

    I approve poplar for the interior, superb wood at $2.00 BF and the white pine for everything else between $0.70 BF to $3.00 BF. depending the knots ratio.
    I think the key of the success is to protect the wood fully.
    I repeat, I still believe that the soaking in a tank of kerosene for a long period of time is very helpful for the longevity of the wood, any wood.
    my own experience over several time never had failed me. But it take a lot of patience, and the soaking as to be repeated after the sawing (of the bevel for example).
    Some slight change of shape can happens during the drying process. You have to deal with that.
    My two cents
  12. hoytedow
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    hoytedow Carbon Based Life Form

    Southern Baldcypress is very good. It holds screws well but is even heavier than fir at about 45# per cubic foot. It is a local wood from Florida.
  13. Petros
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    Petros Senior Member

    doug fir is your best bet. They are using doug fir to build replica aircraft from plans based on sitka spruce, the FAA has approved it as a one to one replacement for stika. IT is a bit stronger and heavier than spruce, but it has good fastener holding properties and it is more rot resistant than spruce as well.

    And since it is so common it is relatively inexpensive. On most smaller boats the weight difference is small, are large boats you might consider having some of the members resized by a competent engineer or NA to take advantage of the higher strength, and that should bring the hull weight in about the same as with sitka spruce.
  14. Boston

    Boston Previous Member

    Wrong on all counts. Dough sucks, has poor rot resistance, is prone to splitting splintering checking warp bow twist and cupping, it's qualities are dependent on where in d tree it is taken from and it's strength to weight ratio varies dramatically based on were it grew. These issues and other preclude it's use in any critical location My two cents. B

  15. Petros
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    Petros Senior Member

    There are only a few species of wood that has better rot resistance than doug fir: cedar, cypress and red wood among a few others. It will rot, but my statement is that it is more rot resistant than spruce. And better than many other speices as well.

    It is stiffer than most woods so it has the reputation of being brittle, but with quality cuts of clear grain doug fir will be dimensionally stable. I do not know what you are talking about, as compared to what?. I have worked with a number of common woods and I find doug fir, if selected carefully makes an excellent structural material. It is stronger than white oak, and weighs and costs less too. I make my living as a structural engineer and 90 percent of the structures I design are out of wood.

    All wood suffer those problems if misshandled or improperly cut. All wood's strength to weight ratio varies with grain count and and other variables, that is why all grown lumber is rated in strength based on drain density, defects and runout. All wood will cup and split if the lumber cut was not done according to the grain orientation. I do not know what you are talking about.

    So what magic wood costs the same or less than doug, is always so perfect it has the same weight and strength, will not rot, warp, split or cup, and is readily available? I have never heard of it.
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