Bamboo backed selfbow

[PaSteve]

 Looking good Arvin. Anticipating the final result.

[mmattockx]

We had a bit of a discussion about how long a power lam had to be to bump you up a class.

According to Alan "A “powerlam” or double wedge in the handle between the belly and backing layer risks reclassification as a Complex-Composite."

I'm not a flight shooter, so this may be a dumb question. If a powerlam will cause a reclassification can you simply put the same taper on the belly lam as what adding a powerlam would give you and avoid the whole problem?


Mark

[Selfbowman]

We had a bit of a discussion about how long a power lam had to be to bump you up a class.

According to Alan "A “powerlam” or double wedge in the handle between the belly and backing layer risks reclassification as a Complex-Composite."

I'm not a flight shooter, so this may be a dumb question. If a powerlam will cause a reclassification can you simply put the same taper on the belly lam as what adding a powerlam would give you and avoid the whole problem?


Yes that’s what I’m thinking. Just make the fade longer.. Arvin


Mark

[Selfbowman]

Boo is glued to the SELFBOW! 
Arvin

[Selfbowman]

Ok question for the guys with trapping experience. Do we trap the back then tiller or as we go. I think on this pyramid trap then tiller. Ok next question. Would 10% of limb width be about right for bamboo to Osage ratio. This is where you smart guys trump me for sure. Arvin

[Rākau]

1 a good caul
2 a good heat gun
3 a good stave
4 ryobi 4x36
5 scrapers I f needed
6 which is supposed come first . Asking for Gods help!
It was easier with the horn because it’s more flexible. That being said I think I can. I think I can. I think I can. 
Arvin

haha fantastic! do you prep your own boo as well?

[Marc St Louis]

I'll say like the others.  Your Bamboo thickness will give you a very heavy bow.  Trapping won't help with that.  All that will do is weaken the backing

Bamboo is heavier than Osage

[Eric Krewson]

When I bamboo back a bow, I have backed about 50 so far, I make every edge of the bamboo stem to stern 1/16" thick, this naturally tapers the bamboo to the tips.

If you make your bamboo very thin you end up with bamboo backed osage bow. If you leave your bamboo thick you will end up with an osage belly bamboo bow with very little osage on the belly at normal poundages.

[Selfbowman]

Well I do have a heavy war bow.  But I have a guy that can pull 100-120#. Marc is the ryne of the boo heaver than the core. My thinking was the boo would override the Osage and it did that’s why I was going to trap the boo and lighten the bow. This thing may end up 1” wide at the fades too. The back did glue up nicely. Arvin

[Selfbowman]

Pic

[Selfbowman]

I did have to small areas that glue did not fill out on the edges . Not bad maybe 1/8” deep. Looks like narrowing the bow will eliminate that.  Arvin

[Selfbowman]

The boo was prepped on the 4x36 ryobi. Some scraping for sure. I will go out on a limb here. This bow will break a record in some weight class in simple composite broadhead.  Arvin

[DC]

Ok question for the guys with trapping experience. Do we trap the back then tiller or as we go. I think on this pyramid trap then tiller. Ok next question. Would 10% of limb width be about right for bamboo to Osage ratio. This is where you smart guys trump me for sure. Arvin

I've trapped the last 3 bows. I did about 1/8" on each side. Don't know if it did anything for speed. Sometimes you just have to do these things blindly and hope. I kinda like the look though

[DC]

We had a bit of a discussion about how long a power lam had to be to bump you up a class.

According to Alan "A “powerlam” or double wedge in the handle between the belly and backing layer risks reclassification as a Complex-Composite."

I'm not a flight shooter, so this may be a dumb question. If a powerlam will cause a reclassification can you simply put the same taper on the belly lam as what adding a powerlam would give you and avoid the whole problem?


Mark

I can't see why there would be any difference. Thickness is thickness unless glue has some magic quality I haven't figured yet. I have just left the boo thicker in lieu of a power lam. It seemed to work.

[mmattockx]

Ok question for the guys with trapping experience. Do we trap the back then tiller or as we go. I think on this pyramid trap then tiller. Ok next question. Would 10% of limb width be about right for bamboo to Osage ratio. This is where you smart guys trump me for sure. Arvin

1) Trap, then tiller.
2) If you want a more precise answer, PM me with your limb dimensions and I will crunch some numbers to try and get you into a more accurate ball park on how much to trap.

Your Bamboo thickness will give you a very heavy bow.  Trapping won't help with that.  All that will do is weaken the backing

Trapping will certainly reduce the weight since it lowers the limb stiffness. It may not reduce the weight enough to make the bow manageable, though.

I can't see why there would be any difference. Thickness is thickness unless glue has some magic quality I haven't figured yet. I have just left the boo thicker in lieu of a power lam. It seemed to work.

I wasn't asking if it would work the same, because it will (as you note). I was asking if using a tapered belly lam avoids the problem with the rules.


Mark