Limb lams and strength/speed

[Machineman]

I am not really a Bowyer, I have made 1 bow. I am thinking of trying again. The question is. I see many different bows from high-end builders that have either non traditional bow woods(Osage,hickory, etc), or even 2 dissimilar types of wood in the same lam. I know that the core of the limb has an effect on speed and strength. However it appears that these makers are doing this without any real detrimental effects. Are these lams super thin? Thanks

[Kirkll]

There are many bowyers building glass backed bows that will tell you that cores do not matter much.... Horse feathers is what i say.... The core materials are subject to tension and compression, and after thousands of arrows that core material can break down and cause a failure.

The most popular core materials for lam bows that have the best longevity is rock hard maple. Period... But bamboo has exceptional tension qualities. If you combine maple on the belly side with bamboo towards the back of the limb, you will find its a wonderful combination...

But you will have different bowyers swear by elm, yew, Zebra, and even clear vertical grain spruce. These are much softer core woods, and lighter in mass weight, and used successfully. The zebra wood has a bit of a brittle nature, but makes a quick bow. I've even used old growth douglas fir lams that held up well for many years, and produced some very high performance.

If you are into building a hot rod bow and going for performance, you can use hickory and paduke, and zebra wood combinations. Even Wenge is a high performance wood.... But... all these woods are very brittle, and the longevity isn't comparable to bamboo and rock hard maple.

They built a lot of carbon backed bows with foam cores years ago, and i built quite a few sets myself that held up well for a limited amount of time. But i believe those foam cores had compression issues over time, and a lot of them came apart delaminating on the belly side.

There's my .02 cents worth...   Kirk

[Machineman]

That's good info thanks. The bow I built was hickory and IPE. Worked pretty good but my daughter broke it one day while stringing it.

[Kirkll]

Building bows with fiberglass backing you will find the core materials used is a bit more forgiving if you are not building radical designs.

But The shape of your limb whether it be a reflex deflex long bow , or a recurve limb,  bends differently depending on your wedge length or fade length on a one piece, and the forward taper rates on your lams.  all these determine the total limb thickness and where the limbs bend exactly, and your working limb length can be manipulated even further with tip wedges and power lams.

Btw….most guys try and keep their laminations thin. I rarely use lams over .080 in thickness.

Laminated wood bows is a whole different ball game that I don’t mess with myself. I already have plenty of firewood… 

[Mad Max]

That's good info thanks. The bow I built was hickory and IPE. Worked pretty good but my daughter broke it one day while stringing it.

Behind the leg, pull the tip around, If not done proper will brake one.
Hickory backed Ipe are a nice combo

[Kirkll]

I honestly think more bows are ruined by improper stringing technique than any other reason.

[Machineman]

Yep, that's what killed it.