Bamboo flooring questions

[DaveMac]

Sorry if these questions have been asked before, I have used the search option and I haven't found quite what I think I need.

I'm planning to experiment with some vertical bamboo flooring that I have, along with a natural bamboo backing strip. I understand that a bow can be made from this material and believe that it is better when backed with natural bamboo.

I have read a re curve build along involving bamboo flooring

   poor folks bows  

and watched this video

   

Anyway the problem is that the bamboo flooring that I have is just 960mm long and 14mm deep so I will have to join four pieces together to make a bow.

I would like some advice on how to proceed. I have a idea on joining the boards together

   

The yellow bar being the natural bamboo and the brown/orange being the flooring.


Three questions

1)Would this be the best way to splice the boards together?
2)Also in the above links two different glues are used epoxy and TBIII any ideas which should I use?
3)Should I build the bow out of flooring then back it or glue the backing on at the start?

[fujimo]

you can Z splice the 'limbs' together in the handle area. then follow up on Roy from pa's threads he build quite a few tri-lams, and that how i would treat it, as a tri lam. taper the core , and the belly , glyue it together on a form of sorts, induce all the shape you want, and build away- but you gotta talk to those guys- they can help you with all the details.
wayne

[LittleBen]

I've spliced core lams and belly lams like you posted and it works fine.

The longer the scarf joiunt the stronger. I'd shoot for at least 1/2" long, preferably 1" long scarf.

You don't have to offset them like that as long as you have a handle block over it all.

[DaveMac]

Just thought offsetting would make it stronger. What glue would you recommend? I've read numerous references to making bows from bamboo flooring, but I haven't found a build along.

[bornofmud]

Bamboo flooring is usually used in the cores of fiberglass bows.  Not sure how common it is in trilams, but of the build alongs I've seen on here I don't think I've seen it used as the limb like that.  

But yeah, should work fine with a nice long scarf joint!  I would also aim for 1" long.  The longer, the better.  And you can offset them or not, if the joint is going to fail, it won't matter if you offset them or not.  As far as them pulling apart after glue up, they should be fine as the riser section doesn't move much.  

For which glue, I would recommend smooth on, it's pretty indestructible stuff, but if it's too much or you already have the tb3, the tb3 will definitely work just fine and is used on many trilams from what I have seen.

[Tim Finley]

I used to buy it in 4x8' sheets like plywood . Dale Stahl has it for sale in long pieces.

[DaveMac]

I havent found the long stuff in the uk. To be honest it was more of an opportunistic buy, and I thought it was worth an experiment with. Thus far it's more of an idea than anything else I'm part way through my first ash board bow, so probably not going to start soon,  I just want to get my plan straight.

[Sam Harper]

You can use a z-splice to splice two boards together, but that will shorten your bow a little.  I make my z-splices 4", which means the over all length will be shortened by 2".  So if my boards are 72" together, that will leave me with 70" after the z-splice.

But I like to put the z-splice in the thickest part of the handle, not where the arrow shelf is going to be.  That requires me to off set the center of the splice by about 1", effectively shortening my board a little more. Does that make sense?

So the center of my bow will be about 1" from the center of the z-splice.  That makes the shorter end of the bow 34" and the longer end 36". To make that the new center of my bow, I cut two inches off the longer end, leaving me with 68".

That's about perfect for a 66" bow because I'll cut my nocks one inch from each end.

If you keep the whole board in tact like that instead of cutting out laminations, just taper from about where the fades are going to be down to the ends.  I haven't made one in a while, but I think my ends were 3/8" or 1/4" or thereabouts.  And I leave them 1.25" wide.

From there, you can tiller to whatever weight you want.

An alternative is to do what you showed in your picture.  Cut the boards into laminations, and do butt splices like you showed in your picture.  I would do an over all 0.002 in/in taper.  You can do that by cutting three laminations, keeping one parallel, and making the other two 0.001 in/in each.  Put the thick parallel lamination on the belly of the bow.  That will give you some room to tiller.

You ought to do something to keep your handle from popping off, too.  There's a couple of ways you can do that.  You can either glue a 20 inch or so "power lam" under the handle between the bamboo backing and the first core lamination, making it tapered on both ends, or you can run your belly lamination up the fades of your riser as if it were a glass lam bow.

Check out the pictures on the bottom of this page to see what I'm talking about:

 http://poorfolkbows.com/ipe1.htm

[PZee]

Dave,

You can by TiteBond 3 at Rutland supplies, Axminster, or over ****. If you can't get it, then use Cascamite (Polymite), but TB is way better. I bought mine from a small hardware store in Buckingham, just outside of Milton Keynes.

Thanks

Pete

[Roy from Pa]

Here is a Z splice and I center the Z splice in the center of the handle grip area. I lay my bow out longer than needed so I can center the splice in the grip area. But an inch either way will not hurt anything. TB3 will work, but smooth on or unibond800 is a better glue.

   

Wrap it with the waxy side of freezer paper towards the glue, have it straight and a block of wood over it, clamp it down and let dry over night for smooth on or unibond800.

   

[DaveMac]

Thankyou for all of your posts.  You guys are extremely generous with your expertise.  I've got quite a bit to think about. Thanks again : )