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Thread: Giving laminates a try....

  1. #1
    Moderator AKmud's Avatar
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    Default Giving laminates a try....

    Ok, here is my latest project.... It is a 64" multi-laminate R/D longbow. Laminates are hickory/jatoba/hickory with a riser of walnut/purple heart/padauk. Not sure what poundage I will have when we're done, but it will be stout I'm sure.

    The glue up -






    Out of the form ...

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    AKmud
    http://i78.photobucket.com/albums/j96/AKmud/213700RMK1-1.jpg


    The porcupine is a peacful animal yet God still thought it necessary to give him quills....

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    Moderator AKmud's Avatar
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    Pretty straight so far -



    The riser woods -

    AKmud
    http://i78.photobucket.com/albums/j96/AKmud/213700RMK1-1.jpg


    The porcupine is a peacful animal yet God still thought it necessary to give him quills....

  3. #3

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    Looking great so far. Nice glue lines on the riser! Are you using a heat box or heat tape to cure the epoxy? I've been thinking about switching from selfbow to laminated bows myself, but haven't made the jump just yet.

    Looking forward to seeing the progress,

    Jeff

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    Moderator AKmud's Avatar
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    Jeff, this one was done only using Titebond III and clamps. I don't have a heat box setup yet (but will be building one this winter). The lines actually came out pretty good with the TB I think. It was a pretty messy glue up though.

    One mistake I made was not listening to the advice I had read on hickory not being good under compression....



    I ended up sanding the entire belly lam off and will probably glue up a different kind of wood for the belly. It was down to 30# @ 28" without the hickory on the belly. I did get the window cut in and handle roughed out so I put about 20 arrows through it last night and it felt solid. I would like to end up in the 42-45# range though.

    Time will tell....
    AKmud
    http://i78.photobucket.com/albums/j96/AKmud/213700RMK1-1.jpg


    The porcupine is a peacful animal yet God still thought it necessary to give him quills....

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    Member Rick P's Avatar
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    Looks great Rob!
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    Bowyer to the forces of light in the land of the midnight sun.
    The 3 fold way: Every step we take as we walk through life effects, our family, our comunity and ourselves. One should walk thoughtfuly.

  6. #6
    Moderator AKmud's Avatar
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    Well.....

    I sanded off the hickory belly lam and glued up an oak lam in its place. Took the clamps off this morning, did some sanding, got 'er looking purty then put it on the tillering wall braced at 6". Things were looking good till I got to 35# @ 26" and she came apart.

    The Jatoba separated at the top of my sight window which I probably cut in too deep.

    Oh well, off to the next one. Time to get some more lumber!
    AKmud
    http://i78.photobucket.com/albums/j96/AKmud/213700RMK1-1.jpg


    The porcupine is a peacful animal yet God still thought it necessary to give him quills....

  7. #7

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    Please allow me to make a few suggestions. I would save your heavy reflex/deflex form for a future fiber-glassed back bow instead of another all wood bow. A durable all wood bow with thin multi-lams is extremely difficult to achieve if you build it similar to fiber-glass construction. Wood cannot take the same stress. Short, high reflex limbs stretch the limits of wood and require perfect tiller to survive. You belly lam was very thin which gives you zero room for tillering. Fiberglass bows often require a small amount of grinding of the belly glass to get a perfect arc but that is measured in thousands so it is not noticed.

    Hickory is better than oak and is fine for belly wood but the limbs must be long and wide. If the belly lam of your bow was osage then you likely would have had the same result. Gluing all your lambs together at the same time will make the bow act as if it has a very thick backing with little neutral wood in the center. This can crush the belly wood. When you ground the belly off and replaced it with another lam you essentially glued a thick back to a thin belly. This is the opposite of what you want.

    Try this: Use a parallel belly lamb no thinner than 1/4". 3/8" is better and will give you some wiggle room. Make a tapered center lam of something like walnut 1/4" thick for the center 12" of the bow and taper it to about 1/8" at the tips. (First) Glue the center and belly lams together flat (straight) the entire length. Protect the upper glue surface of the center lam for your backing strip with tape and soft wood blocks under your clamps. (Second) Use a 1/16" - 1/8" backing strip of hickory and glue it to the center lam. Keep the center 12" flat and reflex the remanding limb about 2" at the tips. (Third) Glue an 8" long handle on the belly to make a 4" handle and 1 1/2"-2" fade-outs.The narrowest part of the fade-outs should be about an inch wide. Don't cut a shelf just glue a leather shelf on later. The handle should be about 1 1/4" wide and 1 1/2" deep. If you are using hickory then make the bow 64"-68" long and 1 3/4" wide for the first 4" of the limb past the fade-outs and then taper down to 1/2" wide at the nocks. I would not use oak unless you want a 2"+ wide 72" long bow. I like to make the top limb about 1" - 1 1/2" longer than the bottom limb. If you tiller properly you should have a durable hunting weight bow.

    A side note: I know Rick P uses Tite Bond III successfully but I am still old school. I use Smooth-on epoxy, or Urac-185. Urac is my my favorite and doesn't need a hot box. Smooth-On or Urac will fill gaps on less than perfect glue lines where Tite Bond needs tighter tolerances. Not an excuse to be lazy but just good insurance. Liquid hide glue is very similar to Tite Bond and is very strong but requires perfect glue lines and an absolute waterproof finish or it will come apart.

    Just my 2 cents.

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    Member Rick P's Avatar
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    Side not to the side note Rick Has successfully used Tite bond III in several experimental bows. Frankly I can't wait to try the other adhesives when I get my shop space moved out of the house. My designs have all been much flater than your's Rob and experiance has definately shown what Boud'arc said to be true. I a nut shell all wood needs to be flater and the belly lam thick.
    BHA Member
    Bowyer to the forces of light in the land of the midnight sun.
    The 3 fold way: Every step we take as we walk through life effects, our family, our comunity and ourselves. One should walk thoughtfuly.

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    Moderator AKmud's Avatar
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    Thanks for the info guys...Boud'arc, thanks for typing all that out. I should throw in the disclaimer that I knew this bow had about 10% chance of surviving, I simply wanted to see what one would look like on my first attempt at a form. It is pretty radical and I think it will sit in the corner for a while...probably until I move in to glass bows. I picked up some more material to make a couple more forms so I will definitely tone the next one down a bit. Experimentation is the name of the game for me since I can't seem to follow the rules!

    Time to go grind out a few more lams now though. (and build another form....)
    AKmud
    http://i78.photobucket.com/albums/j96/AKmud/213700RMK1-1.jpg


    The porcupine is a peacful animal yet God still thought it necessary to give him quills....

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    Moderator AKmud's Avatar
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    Well, here are some pictures of the firewood -

    It had a nice profile prior to coming apart....





    AKmud
    http://i78.photobucket.com/albums/j96/AKmud/213700RMK1-1.jpg


    The porcupine is a peacful animal yet God still thought it necessary to give him quills....

  11. #11

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    that sucks!!! she did look great! Sexy lines too!

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    Member jockomontana's Avatar
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    Nice little wood project, AK Mud...

    I've been wanting to try my hand at a laminate bow for a few years now.

    Anyone have any advice about using Ash? Polyurethane glues?
    thanks!

  13. #13

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    Ash will make a selfbow but it'll need to be 2" wide and 6' long to get a hunting weight bow. I know a guy that back some ash with a strip of maple actionwood. It worked for a while. Maple is closer to ash in the bow wood category. Hickory or bamboo will overpower the ash and cause the ash belly to crush. Polyurethane glue have creep which means they slip at the glue line. Not good for building bows.

    If you want to build a white wood bow then get Paul Comstock's "The Bent Stick". "The Bowyers Bible I" covers white wood pretty good too. Once you've built a bow from osage you'll see that white woods are the AMC Matadors of the automobile industry. It's transportation but you don't see many of them still parked in the driveway.

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