what is the most popular domestic hardwood (US) for cold molding

Discussion in 'Materials' started by Boston, Mar 26, 2010.

  1. Boston

    Boston Previous Member

    so what is your most recommended domestic hardwood for cold molding

    ps
    please dont even remotely recommend Dougy
    firstly its not a hard wood and second Douglas fir is pure crap and having worked with the stuff in the housing industry for years its simply not even the remotest of considerations. I am interested in Domestic hardwoods in the US area and ones that have reasonable rot resistance and stability. The material must not have gluing issues, be rot resistant and readily available

    soon as I figure out how to do it Ill post a pole of the various wood available

    B
     
  2. dskira

    dskira Previous Member

    I suggest to don't use any hard wood for cold moulded.
    You will be on a bad pickle.
    You don't like fir, it's ok, use a light mahogany, like the okume, if you don't like import, use cedar, use what ever you want, but not hard wood for cold moulded.
    Daniel
     
  3. alan white
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    alan white Senior Member

    Quarter-sawn yellow pine would be my first choice for a US wood.
    Hardwood? Hardwoods are heavy for their stiffness. The hull would normally have to be thinner, which would reduce stiffness. Therefore, any hull design would specify wood options. The designer would know what changes in species would do to hull weight. No designer involved?
    Fir is a damn good boat wood for a lot of reasons. Regardless of your experience, having spent many years in the building trades I can attest that fir is strong and relatively rot resistant. It is the wood of choice for decking covered porches tongue and groove style, has been for decades. It is not easy to plane by hand due to the grain being "rowed" or interlocking. However it would be a first-class choice for a domestic cold-molding wood.
    really, of all building methods, cold-molding is among the most amenable to wood choices for reasons other than rot-resistance. It is fully epoxy-encapsulated in and out. It most closely resembles plywood---- is in fact a kind of molded plywood. Rot would only happen if there were a breach due to impact. The physical damage would be simple to locate and repair, or if really extreme, call for being repaired long before rot could set in. Only extreme negligence would allow rot to develop.
    Compare this to a car body. The paint is like the epoxy encapsulation. Steel is used even though it rusts instantly in the presence of water.
     
  4. Boston

    Boston Previous Member

    well then we are right back to poplar
    which I have worked with extensively and has far better characteristics than pine and no worse rot resistance
    after all the rot resistant qualities of a wood are found in its heartwood and the percentage of sapwood in today's yellow pine also known as pitch pine is very high

    poplar is lighter, stronger, and far more readily available. It has been used successfully in the production of small marine craft by at least one famous builder and when encapsulated is just as likely to last just as long and without the inconsistencies of pine.

    basically after 30+ years of hands on working wood and after using pine for a majority of that time I can absolutely assure you of the inferiority of pine.
    Its use being mainly driven by its abundance and not by its quality
     
  5. dskira

    dskira Previous Member

    Your choice of wood will depend also of the shape of the boat. Since one of the layer will be close to 90 degree from the keel, the bilge radius will tell you more that anything else.
    How's the drawing going by the way?
    Daniel
     
  6. Boston

    Boston Previous Member

    drawing is going fine now that I am able to draw again
    thanks for asking
    the old back seems to be feeling a bit better lately

    Ok I got curious about how the actual numbers stack up so I thought Ild dig em up from several sources and lay them out side by side, then compare them by weight and cost

    from wood a manual for its uses in wooden vessels ( US Navy )

    weight ( specific gravity ) yellow pine .58, short leaf .51 hondo .45 poplar .40, red cedar .33 white cedar .32

    fiber stress at proportional limit long leaf yellow pine 9,300 hondo 8,850 short leaf yellow pine 7,700 poplar 6,100 cedar 5,300 w cedar 4,900

    modulus of both rupture and elasticity yellow pine 14,700 and 1,990 short leaf 12,800 and 1,760 hondo 11.140 and 1,430 poplar 9,200 and 1,500, cedar 7,700 and 1,120. w cedar 6,800 and 930

    static bending stress to both proportional limit and maximum load yellow pine 2.44 and 11.8 short leaf 1.93 and 8.2 hondo ( data not available ) and 6.8 poplar 1.43 and 6.8 cedar 1.44 and 5.8 w cedar 1.46 and 4.1

    impact bending at proportional limit in lb/sq inch and impact height to failure yellow pine 15,400 and 34 short leaf 13,600 and 33 hondo ( data not available ) and 22 poplar 13,500 and 20 cedar 8,600 and 17 w cedar 7,600 and 13

    shear parallel to grain and hardness parallel to grain yellow pine 1,500 and 870 short leaf 1,310 and 690 hondo 1,310 and 650 poplar 1,100 and 450 cedar 860 and 350 w cedar 800 and 350



    in an effort to determine the accuracy of my primary source I thought Ild look at another source suggested by another member



    from the wood explorer

    weight ( specific gravity ) Hondo .57 yellow pine .55 short leaf .44 poplar .38 cedar .33 w cedar .29

    bending strength yellow pine 14,117 short leaf 12,834 hondo 11,575 poplar 9,435 cedar 8271 w cedar 5,098

    crushing strength hondo 1,548 yellow pine 941 short leaf 804 poplar 490 cedar 485 w cedar 304

    hardness hondo 1,006 yellow pine 942 short leaf 676 poplar 432 cedar 337 w cedar 322

    impact strength /inches yellow pine 31 short leaf 32 poplar 23 hondo 21 cedar 17 w cedar 13

    shear strength yellow pine 1,633 hondo 1,532 short leaf 1,362 poplar 1045 cedar 945 w cedar 875

    stiffness yellow pine 1,971 short leaf 1,715 poplar 1,506 hondo 1,353 cedar 1,189 w cedar 1011

    work to max load yellow pine 9 short leaf 8 poplar 8 cedar 7 hondo 7 w cedar 5



    so what is the superior wood by weight



    ok not a great way to measure superiority in building characteristics as some measurements translate better than others but still some good food for thought.

    Im going to look at the average weight of each material as derived from both data sets and compare that to a theoretical sample piece of similar weight and suggest that if a one sq/ft piece of yellow pine one inch thick weighing 3.17 lb is compared to a equal mass piece of poplar and also cedar ; what would ( roughly ) the resulting strength characteristics of each be based on its additional thickness. Yellow poplar would be 1.43 inches thick and cedar would be 1.71 inches thick to obtain the same mass sample of all three species at 12x12 inches. Now I realize that there is some gaping flaws in comparing these data points this way but for the most part its just a theoretical look at strength vs mass as opposed to strength vs volume, the later of which is what both the data sets are based on.

    averaging the two data sets
    yellow pine 38 lb/ft3 hondo 37.5 lb/ft3 short leaf 34 lb/ft3 poplar 26.5 lb/ft3 w cedar 23 lb/ft3 cedar 22.25 lb/ft3

    long leaf yellow pine is 1.3% hevier than honduran mahogany 18% hevier than its short leaf cousin, 43.3 % heavier than poplar 70% hevier than eastern white cedar and 71% heavier than western red cedar so how do the numbers compare to an equal weight of each material. Ill convert the wood explorer data set to reflect and equal mass instead of an equal volume and then see how that stacks up against the US navy numbers

    all numbers are converted based on an equal weight of material

    bending strength

    short leaf 15,155
    poplar 14,143
    yellow pine 14,117
    cedar 13,520
    hondo 11,772
    w cedar 8,666

    crushing strength

    hondo 1,574
    short leaf 945
    yellow pine 941
    cedar 829
    poplar 702
    w cedar 516

    hardness

    hondo 1,023
    yellow pine 942
    short leaf 798
    poplar 619
    cedar 576
    w cedar 547

    impact strength

    short leaf 38
    poplar 33
    yellow pine 31
    cedar 29.5
    w cedar 22.1
    hondo 21.35

    shear strength

    yellow pine 1,633
    cedar 1,616
    short leaf 1,607
    hondo 1,558
    poplar 1,497
    w cedar 1,487

    stiffness

    poplar 2,158
    short leaf 2,024
    cedar 2,033
    yellow pine 1,971
    w cedar 1,718
    hondo 1,376

    work to max load

    cedar 11.97
    poplar 11.5
    short leaf 9.44
    yellow pine 9
    w cedar 8.5
    hondo 7.12

    placement based on statistical average

    short leaf 2.1
    poplar 2.9
    yellow pine 2.9
    cedar 3.3
    white cedar 5.6
    Honduran mahogany 4.1


    now the US navy numbers



    fiber stress at proportional limit

    yellow pine 9,300
    short leaf 9,086
    cedar 9,063
    hondo 9,000
    poplar 8,741
    w cedar 8,330

    modulus of rupture

    short leaf 1,510
    yellow pine 14,700
    poplar 13,184,
    cedar 13,167
    w cedar 11,560
    hondo 11,329

    modulus of elasticity

    poplar 2,149
    short leaf 2,077
    yellow pine 1,990
    cedar 1,915
    cedar 1,581
    hondo 1,454

    stress to proportional limit

    w cedar 2.48
    cedar 2.46
    yellow pine 2.44
    short leaf 2.28
    poplar 2.15
    hondo ( data not available )

    stress to maximum load

    short leaf 13
    yellow pine 11.8
    cedar 9.92
    poplar 9.74
    w cedar 6.9
    hondo 6,9

    impact bending at proportional limit

    poplar 19,345
    short leaf 1,604
    yellow pine 15,400
    cedar 14,706
    w cedar 12,920
    hondo ( data not available )

    impact height to failure

    short leaf 39
    yellow pine 34
    cedar 29.07
    poplar 28.66
    hondo 22.4
    w cedar 22.1

    shear parallel to grain

    poplar 1,576
    short leaf 1,545
    yellow pine 1,500
    cedar 1,471
    w cedar 1,360
    hondo 1,332

    hardness parallel to grain

    yellow pine 870
    short leaf 814
    poplar 645
    hondo 661
    cedar 598
    w cedar 595


    placement based on statistical average

    short leaf 1.9
    yellow pine 2.2
    poplar 3
    cedar 3.5
    white cedar 4.9
    hondo 5.2


    characteristics as compared to cost



    what is the cost of the 3000 bd/ft Ill be needing and what would that cost be once adjusted to obtain similar strength characteristics based on going back to the original numbers and considering the percentage of increase to achieve equality for each material

    I buy dead clear straight grained poplar from the mill for less than $1 a foot $2 a foot if I buy it here in town

    I seem to remember paying about $6 a foot for cedar dead clear old growth straight grain but its been a long time since I bought any so that may be way off ( feel free to chime in with your best price ). Ill go with $5 just to be as fair as possible.
    long leaf yellow pine is staging a comeback but is still pricey, Ive not bought any except as flooring in a while but even at that its about $2 a foot for #2 common. Im going to say that dead clear straight grain select is bound to be $4 a foot but just to be fair lets call it $3 just in case anyone has a good handle on some. also Im going to consider short leaf and long leaf at the same cost since both are grouped as yellow pine. I’ll price Mahogany at what I paid last for furniture grade select or $6.75 a foot. I went with Steven's suggestion that eastern white was half the price of western red and so considered $2.50 as the going rate

    per board foot and total for 3000 bd/ft what would I have to spend to get the same strength in each wood in each given category

    honduran mahogany $6.75 = $20,250

    red cedar $5 = $15.000

    yellow pine $3.00 = $9,000

    white cedar $2.50 = $7,500

    poplar $1.50 = $ 4,500

    Mahogany based on what I paid for the last pile I ordered which was not specified as honduran.
    Red cedar Ild likely be paying more like $6 or 7 per ft. Either of the yellow pine brothers, a miracle price, if I could find it, Ild likely be paying more like $5 per ft. Poplar I estimated high just to try and keep things fair, I can buy this material from the mill for <$1 a foot. Eastern white cedar I have no records of purchase to go on

    cost per 3000 bd/ft

    adjusted for modulus of elasticity
    in order of cost

    poplar = $4,500
    long leaf yellow pine - 33% = $6,000
    short leaf yellow pine - 17% = $7,470
    w cedar +61% = $12,096
    red ceder +33% = $20,000
    hondo + 0,48% =$21,241


    adjusted for impact bending

    poplar =$4,500
    long leaf yellow pine -14% =$7,740
    short leaf yellow pine -0.74% =$8,933
    white cedar +77% =$13,322
    hondo -22.5% = $17,719
    red ceder +57% =$23,550


    adjusted for static bending to proportional limit


    long leaf yellow pine -67% = $2,920
    poplar =$4,500
    short leaf yellow pine -35% =$5,850
    white cedar -0.03%=$7345
    ceder -0.69% =$14,900


    adjusted for shear parallel to grain

    poplar =$4,500
    long leaf yellow pine -36% =$5,760
    short leaf yellow pine -19% =$7,290
    white cedar -37% =$10,312
    hondo - 19% = $16,402
    cedar +28% =$19,200



    comparison of characteristics by per bd/ft dollar

    I am recalculating this figure to reflect a comparison to one one board foot material divided by its cost,


    bending strength
    per dollar cost

    poplar 6,290
    yellow pine 4,706
    short leaf 4,278
    w cedar 2,039
    hondo 1,780
    cedar 1,654

    crushing strength

    poplar 326
    yellow pine 313
    short leaf 268
    hondo 229
    w cedar 121
    cedar 97

    hardness

    yellow pine 314
    poplar 288
    short leaf 225
    hondo 149
    w cedar 128
    cedar 57

    impact strength /inches

    poplar 15.3
    short leaf 10.6
    yellow pine 10.3
    cedar 10
    w cedar 5.2
    hondo 3.1

    shear strength

    poplar 696
    yellow pine 544
    short leaf 454
    w cedar 350
    hondo 226
    cedar 189

    stiffness

    poplar 1,003
    yellow pine 657
    short leaf 571
    w cedar 404
    cedar 237
    hondo 200

    work to max load

    poplar 6
    yellow pine 3
    short leaf 2.6
    w cedar 2
    cedar 1.4
    hondo 1

    thing to remember is that some of these numbers do not adjust well to considerations of weight and cost but for the most part I think its a fair way to look at the qualities of a given wood in respect to its use in any building project

    cheers
     
  7. peter radclyffe
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    peter radclyffe Senior Member

    larch on larch ?
     
  8. Boston

    Boston Previous Member

    Ive worked with miles of that stuff
    still a fir ( usually Douglas rather than larch anyway ) and as such has pretty poor rot resistance and really bad consistency even within the same tree let alone the same forest
    if Im encapsulating the wood in epoxy anyway then why not a superior wood with the same rot resistance

    I must admit Im baffled by this fascination with the pines for naval applications
    once upon a time yellow pine might have been worthwhile but with all the old growth being used up and everything now being farmed its simply doesn't have the characteristics it once had
     
  9. Boston

    Boston Previous Member

    oh hey Peter if you get a chance go to a mill thats cutting Larch Fir and check it out
    huge amount of waste as boards come off the saw
    they literally curl before your eyes before the next board is cut and stacked over it
    then there is the stuff that doesn't make it out of the kiln
    I posted an article around here somewhere about this
    Ill try and look it up

    B
     
  10. rasorinc
    Joined: Nov 2007
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    rasorinc Senior Member

    Bos, without going into detail like you did, there is a performance grade of lumber for all common species. Weyerhaeuser calls it performance grade and I knew it as 2400 series lumber. Machine graded for density and it is heavier then standard and tougher to drive a nail--a lot harder. It is used for making floor and roof trusses. Yesterday I was at a truss plant here in Tennessee specifically to look at this lumber and parallelams for boat building. This company is large here in TN. I got quite an education on all products and you can really tell the difference in the denser wood--mostly by weight. It can be bought in 20' lengths down to 4' and 5' lengths used for webbing. It does not change the rot factor though so complete sealing with epoxy is necessary but for strength the density factor is huge. Weyerhaeuser. com
    talks about performance grade lumber. A couple of pieces I picked up felt almost like ironwood--you could make bats our of it and this was southern yellow pine and spruce-not old growth but the new fast growth seedings (15 years). Just some more info to your excellent posting. Stan
    I would still prefer Black Locust if I could find the lengths and the price because NO ROT. The lumber above is $.80 to $1.00 a board foot.

    I fell in love with this boat put a hull like this under your classic and have the best of both worlds.

    http://www.boatdesign.net/gallery/showphoto.php/photo/2251
     
  11. troy2000
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    troy2000 Senior Member

    As far as Douglas Fir goes, there's Douglas Fir and Douglas Fir. It's definitely not all created equal. I remodeled old homes in Los Angeles from the early 1900's, and the old-growth DF they were built with had nothing in common with the stuff you see at Lowes or Home Depot.

    The grain was so tight it looked like a series of pencil lines spaced a line's-width apart, instead of having big, spongy masses of springwood--like plantation DF has. It was so hard that I often had to drill slightly undersized holes to get nails into it (I assume it must have been green when originally nailed together).

    If I had access to old-growth DF like that, I wouldn't hesitate to use it structurally or any other way, anywhere in a boat. As I've mentioned before, many of the old West Coast lumber schooners were Douglas Fir from top to bottom.
     
  12. Boston

    Boston Previous Member

    all true but
    we are talking about a modern cold molded hull
    Dougy is heavy it splits splinters and it twists more often than not, it was used because it was so common. Not because it was the superior wood.

    these days I have good access to just about all the domestic hardwoods and at dam low prices.

    the frustrating thing is that of all the woods Ive looked at Poplar comes out on top in nearly all categories both in bang for the buck and in most other regards
    specially when compared by weight
    lb for lb is it vastly superior to almost all the firs in nearly all categories
     
  13. rasorinc
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    rasorinc Senior Member

  14. troy2000
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    troy2000 Senior Member

    I'm surprised to hear you talking about DF like it's a second-class wood. Again, it depends on which grade of Douglas fir you're talking about. It doesn't have any more tendency to twist than any other commonly used woods, in my experience. Overall, it's actually one of the more dimensionally stable woods. It not only air dries or kiln dries well if properly handled, but it's one of the best woods for seasoning in place--which is why most of it in the construction trade is shipped green, and nailed together while it's still juicy and soft.

    And it's also an excellent finish wood. to quote the WWPA, "Douglas Fir's characteristics make it ideal for joinery: doors, millwork, window and door casings, mantels, stairs and baseboards. When dry, it retains its shape and size and won't check or show a raised grain. Additionally, Douglas Fir has an excellent performance record when used in exposed applications for exterior trim without ground contact."

    I'm not the Messiah of DF. I don't care whether you use it or not, and I'm sure there are more cost-effective woods out there for cold molding than decent-grade Douglas Fir. But it works well when used that way. As a matter of fact, the second USS Constellation, originally built in 1853 as the last pure sail US Navy ship, has been rebuilt with Douglas Fir cold molded outer planking. It allowed them to save more of the original framing, which was no longer strong enough to handle another round of traditional planking and fasteners..
     

  15. alan white
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    alan white Senior Member

    Within the same species there is a vast difference between one board and another if we each arrive with our own boards to compare. I look for densely grained wood, quarter-sawn, free of pitch pockets, shakes, and straight-grained. I prefer it green to begin with.
    There are still some trees that produce good boards. Hard pines can be found---- sometimes in old beams or posts. Yoiu can simply accept what is on the market and order it delivered---- I suppose for a big project, you have no choice. You receive what the industry calls "fir" or "yellow pine".
    The truth is, you have to become an expert at choosing good boards. That means knowing what to look for, not the wood's name, but the actual plank or board. It can't be taught in a book. Some of you know what I mean. Novices will have to learn the hard way, the school of hard knocks.
    Working with wood involves more than technical information. Like playing a musical instrument, some of the knowledge comes through years of trials and tribulations. Even all this good advice is general, and exceptions abound.
    Go with the consensus for now, but one day, years from now if you stick with it, you'll develop another sense of wood that is better than any general knowledge available.
     
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