Well I am attempting my first all wood lam longbow and everything was going great, until SNAP. You all have heard that sound (I assume) and this was my first. Heartbreaking to say the least. But, it wasn't a total loss and I am not one to throw something away that I have spent a lot of time on. So I attempted to fix it.
Here is what happened. The bow started out with Elm on the back, Walnut-Bamboo-Walnut as a core and Black locust on the belly. I was getting it tillered and all was well. I did have to take quite a bit out of the belly as it was very stiff. But all was well and right on target. Got to the point when I was ready to brace it up. While putting the sting on, thats when that infamous SNAP happened. My head dropped and I just dropped the bow without even looking at it. Stood there for a minute and then looked down to see the damage. It was just the two back layers. It was the Locust the the next layer of Walnut. Nothing else was damaged. So I grabbed the bow and went right over to the sander and removed those two layers. So now I have three solid layers left with the middle bamboo on the back. It was now pretty weak and needed something put on the back. I grabbed a piece of bamboo and glued it on the back. Looking great, but this is where I need your help. Talk about stiff as a board. I can hardly budge this thing now.
What do I do now. Do I keep shaving the belly which I will pretty much remove all the elm and be left with walnut. Or is there something else to do?
Here is what I have now. As you will see, the belly is already almost down to nothing on the tips.
(http://i210.photobucket.com/albums/bb262/MSCustomCalls/SU1HMDAyMzUtMjAxMTAzMDQtMjIyMy5qcGc.jpg)
(http://i210.photobucket.com/albums/bb262/MSCustomCalls/SU1HMDAyMzYtMjAxMTAzMDQtMjIyNC5qcGc.jpg)
(http://i210.photobucket.com/albums/bb262/MSCustomCalls/SU1HMDAyMzgtMjAxMTAzMDQtMjIyNS5qcGc.jpg)
That super thin core will probably come back to nip ya' Matt. If you can get the de-lam to stay together I would tiller with your width and leave the the thickness alone, at least 8-10" of the tips anyway.
That super thin is the belly near the tips. After tillering the first time, I had to remove quite a bit. Its got a pretty good taper from fade to tip on the belly lam.
How thick is your bamboo on the outside edges. It looks a little thick from the picture.
It may end up too strong for the belly.
You might consider tapering the bamboo back from the edges about 3/16" so the edge ends up 1/16 or less thick.
By removing some of the bamboo it will help with the weight and help reduce tension some.
Ron
Here is the thickness of what I have at the taper and what is at the tip.
If I take anymore out of the belly I will well into in the walnut core. Do you think I take enough off the edge of the back bamboo that it will make enough of a difference.
At the end of the fade
(http://i210.photobucket.com/albums/bb262/MSCustomCalls/SU1HMDAyMzktMjAxMTAzMDUtMTQzOS5qcGc.jpg)
At the tip
(http://i210.photobucket.com/albums/bb262/MSCustomCalls/SU1HMDAyNDAtMjAxMTAzMDUtMTQzOS5qcGc.jpg)
That bamboo is waaaay too thick, especially for the weak woods it's backing. That said...start trapping. Don't touch the belly anymore. It's not the strength of compression you're fighting now. It's tension. Leave the belly full width & start reducing from the sides at the back of the stack.