carbon and foam core limbs

[skinner biscuit]

#6781

I was on the phone with Ron Pittsley of Hunters Niche and I asked him about carbon and foam core limbs. He told me he didn’t really see a difference between them and standard limbs, that all I would be doing is giving him another hundred bucks.What’s your thoughts on this?

[Stephen Graf]

#55094

The “advantage” to foam cores is mainly for long range field archery where temperature can affect the limbs. The “advantage” is supposedly in the dimensional stability of the foam regardless of temperature and humidity. Beyond that, there is no advantage.

The density of the foam used in bow limbs is just a bit higher than bamboo, and the foam has no elastic properties. From what I’ve been reading, it looks like the foam is not as durable as wood cores either.

For a hunter, there is no need of foam. I think Ron is right.

[jpc]

#55146

With Foam and carbon you can have same arrow at 42 Lbs than a BW at 55

same arrows, same archer, same draw length

And the bow is stronger against torque than any other one without carbon

Ford or Ferrari can do same trip, but there is some différence

Why not have the best when money is not a problem

some console themselves by saying that carbon is unnecessary but would be happy if they could have one to try

[jpc]

#55338

All foam cores or composite cores are equal. Some are made with polyurethane resins and the stronger materials made with the more expensive Epoxy resins. The density and strength of the material is based on the percentage of filler to resin and the characteristics of the material is based on what filler bulks out the resin system, stronger weaker lighter heavier more dimensionally stable less dimensionally stable. The elasticity of the core is meaningless. Lets assume that the composite core is half as elastic strong as bamboo. Okay then here is an example just and example and not and actual situation just and approximation, then assuming the bamboo core alone without the composite bow facings generates a bow drawweight of 1Llbs and the composite core .75lbs and the bow weight is 55lbs So the bamboo core is responsible for 1.8% of the drawweight and the Composite core is responsible for 1.3% so the difference in bow weight generated is 0.5%. 0.5% is nothing and would hardly affect the speed at all. However a 20% weight reduction in core mass is about a 7% mass reduction in the whole limb and that is significant and represents about 2 fps. But some composite cores will be roughly the same weight as the wood core and so no different.

not all composite core materials are equal.

Hyperflex cores are lighter in weight over wood cores by approx. 20% and that gives the bow 2 to 3 fps speed advantage. Also due to the lower limb mass there is less hand shock and so a smoother after shot and lower vibration

[Jason Wesbrock]

#55580

I’ve competed, hunted and taken game with everything from selfbows to carbon/foam limbs on metal risers. Some of them I build; most of them I bought. Here’s my take on it.

Carbon/foam limbs have been the gold standard in Olympic archery for the past few decades, long before they were ever on the radar of traditional bowyers. The average male Olympic shooter pulls over 50# and shoots arrows well over 210 fps. My personal target setup handles 5.5 gpp at my 32” draw length without so much as a hint of a problem. Most traditional bowyers will void their warranty if you shoot under 8 gpp; some 9 gpp. The carbon/foam limbs I shoot have no such restrictions. They’re durable enough to handle it.

Carbon/foam limbs are also substantially more stable than their wood/glass counterparts. As a result, it’s all but impossible to twist them—I’ve never heard of a set of Olympic carbon/foam limbs developing such a problem—and they are much for forgiving of torque. They are also impervious to changes in weather conditions. Whether it’s 90 and sunny in July, 40 and raining in April, or -20 in December, they will shoot exactly the same from shot to shot.

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