Spline/Batten material & how to splice?

Discussion in 'Boat Design' started by abosely, Sep 11, 2015.

  1. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 491, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Yeah, I too look for these and SYP stock. I can get perfectly clear stuff pretty regularly, 16' long, in the 2x10 ans 2x12 piles.
     
  2. LP
    Joined: Jul 2005
    Posts: 1,414
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Doesn't that grain density just bring a smile to you face, Paul. :D. I think I could build my mast out of this stock though it is extraordinarily heavy.
     
  3. abosely
    Joined: Mar 2015
    Posts: 136
    Likes: 1, Points: 18, Legacy Rep: 10
    Location: Big Island Hawaii

    abosely Senior Member

    Wow LP, that is beautiful! I'll have to start going in 'treasure hunts' now myself. :)

    Cheers, Allen
     
  4. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 491, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I find Douglas fir with tight grain frequently. I don't even have to look, as I'm going though a pile several will be much heavier than the others and these will usually have a much higher grain density. SYP is nearly all farm raised now, so the density is fairly low, but the wider stock usually yields some good stuff.
     
  5. Jammer Six

    Jammer Six Previous Member

    There's good wood in every piece.

    The question isn't whether it's there, the question is is it worth the money and the labor to get it out.

    The disadvantages the big box stores have is that one, they can't inspect every piece they buy, and two, they let everyone pick through every pile for every piece they buy, and therefore people can beat you to the good wood.

    The advantage is they let everyone pick through every pile for every piece they buy, so you can choose every piece you buy. Back In The Day, depending on the size of the order, that wasn't always the case at ordinary lumber yards. You bought three pieces of clear fir for trim, and they'd let you pick them out, if you knew the guy. You bought four slings of plate material, you took what came off the pile as it came off the pile.

    The reason there is better wood in large pieces is because mills use the better wood to cut large pieces. (Because they get more large pieces out of good wood. The all-powerful yield is higher.) So if you buy larger (in width, thickness and length) material than you need, you will get better wood. But then you will have to cut the wood you want out of those bigger pieces, and there will be more waste. You will trade money (for wasted material) and labor for higher quality wood.

    Larger pieces cost more to transport, store, handle and cut. The equipment cost more, you need a rack on your pickup, etc., etc. If you don't believe me, take a nice, wet eighteen foot 4x6 and try to rip a 2x4 out of it on a Craftsman homeowner's tablesaw, or try to bring it home in a Volkswagen Beetle. Or just carry it around alone until you believe me.

    So the bottom line is that there is good wood in every piece -- it's just that it may be 1/16" thick, half an inch wide and two inches long. The question is whether it's worth your time and money to get it out.
     
  6. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 491, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Thanks Mr. Obvious another helpful post.
     
  7. LP
    Joined: Jul 2005
    Posts: 1,414
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Ok. This is as good of place to ask this as any. It's kind of directed at PAR because I'm using a drawing of his as illustration.

    image.jpg

    I've always worked with scarfs on the premise that scarf ratio was based on the the slope of the cut. Run over rise. In this attachment, the scarf length is based on the width of the board, regardless of orientation. Scarfed across the minor dimension, this makes sense. Scarfed across the greater dimension, the ratio is increased to a greater ratio. The amount of joining surface is much greater in the second scenario. I think that the first illustration on the left side of the attachment is correct. I the middle illustration is not an 8 to 1. I think that the bottom illustration is also correct.

    I only bring this up because I have been thinking about scarf joints and the most efficient use of material. Scarfing across the major dimension, top and middle, will net the shortest scarf while maintaining the appropriate slope. Scarfing across the minor will net a longer joint, lower illustration, while maintaining the desired slope, but use more material. An 8 to 1 scarf is 7 degrees (ish) regardless of board orientation.

    The question: Is there a difference in joint strength depending on whether the scarf is cut across the major on minor dimension of the board.
     
  8. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 491, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    All three drawings are correct and it depends on what you want. On deadwood assemblies you'll use the width, which is usually shorter than the height. Using the height on these would make scarfs too long. On a mast, it's more common to use stave thickness (generally 12:1), again to keep scarf lengths reasonable. This drawing is just to show how to arrange the scarf ratio, but is dependant on the application. The drawing wasn't precisely scaled, but is pretty close. This drawing is one of several that go with all my plan sets, as generic instructions and information. As a rule a scarf is used to provide sufficient glue on the faying surfaces, but with modern adhesives you can get by with less. I'll have a look at the original drawing and see how far off it might be on the middle sketch.

    I just noticed Mr. Obvious above is now a "Previous Member". I guess he pissed more than me off. He did have some points occasionally (I actually agreed with him a few times), but he never found a way to justify his discontent or whatever was usually up his butt.

    I'll get back to you on the scarf drawing.
     
  9. upchurchmr
    Joined: Feb 2011
    Posts: 3,272
    Likes: 250, Points: 83, Legacy Rep: 579
    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member

    PAR,

    You need to get back to me too, cause I can't see any justification for calling the top and the middle scarfs both 8/1.

    I can understand wanting to change the ratio for a given task, but the middle illustration would give an different angle of the tapered portion of the board dependent up the arbitrary choice of width of board.

    Is there something more than describing a selected angle on the taper involved in your definition? 8/1 slope to me describes 7.12 degrees. Making the middle one an 8/1 would change it to much less than 7.12 degrees.
     

  10. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 491, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    This is the same artwork with the 8:1 ratio shown. I was right, it was slightly off, but in this resolution, very difficult to see. The difference for illustration purposes was good enough. Note the lower two images use the width, while the top image uses the thickness to work the ratio. Any of the dimensions can be employed in a scarf.
     

    Attached Files:

Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.